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Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

For which of the following reasons can natural pollutants play an important role in controlling air pollution?

A. They're less harmful to living beings than other pollutants. 

B. They function as part of a purification process.

C.They occur in greater quantities than other pollutants.

D. They have existed since the Earth developed.

1
15 tháng 10 2018

Kiến thức: Đọc hiểu

Giải thích:

Vì lý do nào sau đây, các chất gây ô nhiễm tự nhiên có vai trò quan trọng trong việc kiểm soát ô nhiễm không khí?

A. Chúng ít gây hại cho cuộc sống hơn các chất gây ô nhiễm khác.

B. Chúng hoạt động như một phần của quá trình thanh lọc.

C. Chúng xuất hiện với số lượng lớn hơn các chất gây ô nhiễm khác.

D. Chúng đã tồn tại kể từ khi Trái đất phát triển.

Dẫn chứng: Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil

Tạm dịch: Nhiều chất ô nhiễm không khí quan trọng hơn, chẳng hạn như oxit lưu huỳnh, carbon monoxit và nitơ oxit được tìm thấy trong tự nhiên. Khi Trái đất phát triển, nồng độ của các chất gây ô nhiễm này đã bị thay đổi bởi các phản ứng hóa học khác nhau; chúng trở thành các thành phần trong chu kỳ sinh hóa. Chúng phục vụ như là một chương trình lọc không khí bằng cách cho phép các hợp chất di chuyển từ không khí đến nước hoặc đất.

Đáp án: B

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34. An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.

What does the passage mainly discuss?

A. The economic impact of air pollution.

B. What constitutes an air pollutant. 

C. How much harm air pollutants can cause. 

D. The effects of compounds added to the atmosphere.

1
21 tháng 5 2019

Chọn B.

Đáp án là B.

Giải thích: Bài văn chủ yếu bàn về :

A. Tác động về mặt kinh tế của ô nhiễm không khí

B. Những gì hợp thành 1 tác nhân ô nhiễm không khí

C. Mức độ nguy hại mà chất ô nhiễm gây ra

D. Ảnh hưởng của các hợp chất bị thêm vào không khí

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34. An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.

According to the passage, human-generated air pollution in localized regions ___.

A. can be dwarfed by nature’s output of pollutants

B. can overwhelm the natural system that removes pollutants 

C. will damage areas outside of the localized regions 

D. will react harmfully with natural pollutants

1
1 tháng 8 2017

Chọn B.

Đáp án là B.

Giải thích: 

Đoạn 3: However, human production usually occurs in a LOCALIZED area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34. An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.

The word "adversely" in the first paragraph is closest in meaning to _______.

A. negatively

B. quickly

C. admittedly 

D. considerably

1
21 tháng 6 2017

Chọn A.

Đáp án là A.

Giải thích: Từ “adversely: 1 cách tiêu cực/bất lợi” gần nghĩa nhất với từ nào sau đây?

A. negatively: tiêu cực

B. quickly: nhanh chóng

C. admittedly: thừa nhận rằng

D. considerably: đáng kể

Dịch: An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials ADVERSELY.

(Một chất gây ô nhiễm không khí được định nghĩa là một hợp chất được đem trực tiếp hoặc gián tiếp vào khí quyển bởi con người ở một khối lượng gây ảnh hưởng đến con người, động vật, thực vật hay các nguyên liệu khác một cách tiêu cực.)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the...
Đọc tiếp

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

According to the passage, human- generated air pollution in localized regions ______.

A. will react harmfully with natural pollutants. 

B. can overwhelm the natural system removing pollutants. 

C. will damage area outside of the localized regions. 

D. can be dwarfed by nature's output of pollutants.

1
9 tháng 12 2019

Kiến thức: Đọc hiểu

Giải thích:

Theo đoạn văn, ô nhiễm không khí do con người tạo ra ở các vùng địa phương _______.

A. sẽ phản ứng vô hại với các chất gây ô nhiễm tự nhiên.

B. có thể áp đảo hệ thống tự nhiên loại bỏ các chất gây ô nhiễm.

C. sẽ làm hỏng khu vực bên ngoài các khu vực địa phương hóa.

D. có thể bị lấn át bởi sản lượng của các chất gây ô nhiễm.

Dẫn chứng: However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. Tạm dịch: Tuy nhiên, sản xuất của con người thường xảy ra ở một khu vực địa phương, chẳng hạn như một thành phố. Trong một khu vực như vậy, sản lượng của con người có thể chiếm ưu thế và có thể tạm thời quá tải kế hoạch thanh lọc tự nhiên của các chu kỳ.

Đáp án: B

  Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34. An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the...
Đọc tiếp

 

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.

It can be inferred from the first paragraph that __________.

 

A. water vapor is an air pollutant in localized areas 

B. most air pollutants today can be seen or smelled 

C. the definition of air pollution will continue to change 

D. a substance becomes an air pollutant only in cities

1
11 tháng 4 2018

Chọn C.

Đáp án C.

Giải thích : Đáp án nằm ở : “Air pollution requires a very flexible definition that permits continuous change.”

(Ô nhiễm không khí cần có 1 định nghĩa linh hoạt cho phép những thay đổi liên tục.)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the...
Đọc tiếp

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word “adversely” in the first paragraph is closest in meaning to ______.

A. considerably

B. quickly

C. admittedly 

D. negatively

1
17 tháng 3 2018

Kiến thức: Đọc hiểu Giải thích:

Từ “adversely” ở đoạn 1 gần nghĩa nhất với _____.

A. đáng kể                    B. nhanh chóng          C. thừa nhận              D. tiêu cực

Dẫn chứng: An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely.

Tạm dịch: Một chất gây ô nhiễm không khí được định nghĩa là một hợp chất được thêm trực tiếp hoặc gián tiếp bởi con người vào khí quyển với số lượng như vậy ảnh hưởng đến con người, động vật, thực vật hoặc vật liệu một cách tiêu cực.

Đáp án: D

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34. An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.

The word “These” in the second paragraph is closest in meaning to _______.

A. The various chemical reactions 

B.The pollutants from the developing Earth 

C.The compounds moved to the water or soil 6 

D. The components in biogeochemical cycles

1
4 tháng 3 2019

Chọn D.

Đáp án D.

Giải thích:

Từ "these" trong đoạn thứ hai là gần nhất trong ý nghĩa với__________:

A. Các phản ứng hóa học khác nhau

B. Các chất gây ô nhiễm từ trái đất đang phát triển

C. Các hợp chất chuyển đến nước hoặc đất

D. Các thành phần trong chu kỳ sinh địa hóa

Ý trong bài : “As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil.”

(Khi Trái đất phát triển, sự tập trung vào các nhân tố gây ô nhiễm này bị thay đổi bởi các phản ứng hoá học, chúng trở thành những phần tử nằm trong chy kỳ hoá sinh. Những phần tử này hoạt động như 1 chu trình làm sạch không khí bằng cách cho phép các hợp chất này di chuyển từ không khí sang nước hay đất.)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the...
Đọc tiếp

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

According to the passage, the numerical value of the concentration level of a substance is only useful if .

A. it can be calculated quickly

B. it is in a localized area 

C. the natural level is also known 

D. the other substances in the area are known

1
29 tháng 8 2017

Kiến thức: Đọc hiểu

Giải thích:

Theo đoạn văn, giá trị số của nồng độ của chất chỉ hữu ích nếu _______.

A. nó có thể được tính toán một cách nhanh chóng

B. nó đang ở trong một khu vực địa phương hóa

C. mức độ tự nhiên cũng được biết đến

D. các chất khác trong khu vực được biết đến

Dẫn chứng: The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.

Tạm dịch: Nồng độ thực tế không cần phải lớn để một chất là chất gây ô nhiễm; trên thực tế, giá trị số cho chúng ta biết rất ít cho đến khi chúng ta biết mức tăng này thể hiện qua sự tập trung có thể xảy ra tự nhiên trong khu vực như thế nào.

Đáp án: C

Dch bài đc:

        Ô nhiễm không khí được định nghĩa là một hợp chất được thêm trực tiếp hoặc gián tiếp bởi con người vào khí quyển với số lượng như vậy ảnh hưởng đến con người, động vật, thực vật hoặc vật liệu bất lợi. Ô nhiễm không khí đòi hỏi một định nghĩa rất linh hoạt cho phép thay đổi liên tục. Khi các luật ô nhiễm không khí đầu tiên được thành lập ở Anh vào thế kỷ 14, các chất gây ô nhiễm không khí bị giới hạn bởi các hợp chất có thể nhìn thấy hoặc ngửi - một tiếng kêu xa từ danh sách các chất độc hại ngày nay. Khi công nghệ đã phát triển và kiến thức về các khía cạnh sức khỏe của các hóa chất khác nhau đã tăng lên, danh sách các chất gây ô nhiễm không khí đã kéo dài. Trong tương lai, ngay cả hơi nước có thể được coi là một chất gây ô nhiễm không khí trong những điều kiện nhất định.

        Nhiều chất ô nhiễm không khí quan trọng hơn, chẳng hạn như oxit lưu huỳnh, carbon monoxit và nitơ oxit được tìm thấy trong tự nhiên. Khi Trái đất phát triển, nồng độ của các chất gây ô nhiễm này đã bị thay đổi bởi các phản ứng hóa học khác nhau; chúng trở thành các thành phần trong chu kỳ sinh hóa. Chúng phục vụ như là một chương trình lọc không khí bằng cách cho phép các hợp chất di chuyển từ không khí đến nước hoặc đất. Trên cơ sở toàn cầu, sản lượng của các hợp chất này là do sao lùn tạo ra từ các hoạt động của con người.

        Tuy nhiên, sản xuất của con người thường xảy ra ở một khu vực địa phương, chẳng hạn như một thành phố. Trong khu vực như vậy, sản lượng của con người có thể chiếm ưu thế và có thể tạm thời làm quá tải kế hoạch thanh lọc tự nhiên của các chu kỳ. Kết quả là nồng độ các hóa chất độc hại trong không khí. Nồng độ mà tại đó các tác dụng phụ xuất hiện sẽ lớn hơn nồng độ các chất gây ô nhiễm sẽ có trong trường hợp không có hoạt động của con người. Nồng độ thực tế không cần phải lớn cho một chất là chất gây ô nhiễm; trên thực tế, giá trị số cho chúng ta biết rất ít cho đến khi chúng ta biết mức tăng này thể hiện qua sự tập trung có thể xảy ra tự nhiên trong khu vực như thế nào. Ví dụ, sulphur dioxide có thể phát hiện được hiệu ứng sức khỏe ở mức 0,08 phần triệu (ppm), gấp khoảng 400 lần mức độ tự nhiên của nó. Carbon monoxide, tuy nhiên có mức độ tự nhiên 0,1 ppm và thường không phải là chất gây ô nhiễm cho đến khi đạt đến mức 15 ppm.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the...
Đọc tiếp

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

        An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

        Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

        However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

It can be inferred from the first paragraph that ______.

A. the definition of air pollution will continue to change. 

B. Most air pollutants today can be seen or smelled. 

C. a substance becomes an air pollutant only in cities. 

D. water vapor is an air pollutant in localized areas.

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12 tháng 8 2017

Kiến thức: Đọc hiểu

Giải thích:

Có thể suy ra từ đoạn văn thứ nhất rằng _______.

A. định nghĩa về ô nhiễm không khí sẽ tiếp tục thay đổi.

B. Hầu hết các chất gây ô nhiễm không khí ngày nay có thể được nhìn thấy hoặc ngửi thấy mùi.

C. một chất trở thành một chất gây ô nhiễm không khí chỉ ở các thành phố.

D. hơi nước là một chất ô nhiễm không khí trong khu vực địa phương hóa.

Dẫn chứng: Air pollution requires a very flexible definition that permits continuous changes.

Tạm dịch: Ô nhiễm không khí đòi hỏi một định nghĩa rất linh hoạt cho phép thay đổi liên tục.

Đáp án: A