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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 following questions                                The ability to conduct electricity is one of the key properties of  a metal. Other solid material such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved  in water. The ability of metals to...
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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 following questions                               

The ability to conduct electricity is one of the key properties of  a metal. Other solid material such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved  in water. The ability of metals to conduct electricity is due to how their atoms bond together. In order to bond together the metal atoms lose at least one of their outermost  electrons. This leaves the metal atoms with a positive charge and they are now strictly  ions. The lost electrons are free to move in what are known  as a sea of electrons. Since the electrons are negatively charged they attract the ions and this is what keeps the structure together.

            An electric current is a flow of charge and since the electrons in the sea of electrons are free to move they can be made to flow in one direction when a source of electrical energy such as a battery is connected to the metal. Hence we have an electric current flowing through the wire, and this is what makes metals such good conductors of electricity. The only other common solid conducting material that pencil users are likely to encounter is graphite (what the ‘lead’ of a pencil is made from). Graphite is a form of carbon and again the carbon atoms bond in such a way that there is a sea of electrons that can be made to flow as an electric current. Likewise, if we have an ionic substance like salt we can make the electrically charged ions flow to create a current but only when those ions are free to move, either when the substance is a liquid or dissolved in water. In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow. Freshwater Aquarium Fish

Playlist Freshwater Aquarium Fish

       Electrical insulators are substances that cannot conduct electricity well either, because they contain no charged particles or any charged particles they might contain do not flow easily. Water itself is a poor conductor or electricity as it does not contain a significant amount of fully charged particles (the ends of a water molecule are partly charged but overall the molecule is neutral). However, most water we encounter does contain dissolved charged particles, so it will be more conductive than pure water. Many of the problems that occur when touching electrical devices with wet hands result from the ever-present salt that is left on our skin through perspiration and it dissolves in the water to make it more conductive.

By Helena Gillespie and Rob Gillespie. Science for Primary School Teacher. OUP

Salt in its solid state is not able to conduct electricity because                    .  

A.  it has free electrons

B.  its charged ions can flow easily 

C. it cannot create any charge ions

D. it charged ions are not free to move

1
17 tháng 3 2019

Đáp án : D

Cuối đoạn 2: In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow.

26 tháng 9 2019

Đáp án: D

Giải thích: Mấu chốt của câu này là các em phải đọc hết đoạn cuối để suy ra cái mà tác giả muốn hướng tới: Con người phải đối mặt với sự lựa chọn khó khăn: sự sống của mình hay cứu lấy động vật.

7 tháng 4 2018

Đáp án: C

Giải thích: Chúng ta thấy câu C sai luôn khi đọc đến dòng 4, dòng 5 của đoạn 2.

30 tháng 5 2019

Đáp án A

Refuse + to V = từ chối làm gì

Avoid + V-ing = tránh làm gì

Deny + V-ing = phủ nhận làm gì     

Bother + to V = phiền làm gì

→ Dùng “refused” để phù hợp ngữ cảnh

Dịch: Bộ trưởng từ chối cho ý kiến liệu tất cả các mỏ than sẽ bị đóng.

10 tháng 9 2018

Đáp án: A

Giải thích: Ở cuối câu 1 đoạn 2, tác giả có nhắc đến việc cách dùng chuẩn được chấp nhận bởi số đông mọi người ở bất kì hoàn cảnh nào, không cần tính đến mức độ trang trọng.

19 tháng 4 2017

Đáp án B.

Key words: main idea of the passage.

Trong đoạn 1, 2 tác giả nêu ra rằng âm nhạc Mĩ khởi nguồn từ những người Mĩ gốc Phi; nhưng không ai bận tâm ghi chép về những người đã mang âm nhạc từ quê hương họ tới Mĩ.

Đoạn cuối nói rằng người ta thật khó biết tên của những người đã khơi nguồn cho truyền thống âm nhạc này ở Mĩ. Do đó, đáp án đúng phải là B. it is hard to exactly recognize the people who started the American musical tradition: Thật khó để xác định chính xác những người khởi đầu cho truyền thống âm nhạc ở Mĩ.

17 tháng 12 2017

Đáp án B.

Key words: main idea of the passage.

Trong đoạn 1, 2 tác giả nêu ra rằng âm nhạc Mĩ khởi nguồn từ những người Mĩ gốc Phi; nhưng không ai bận tâm ghi chép về những người đã mang âm nhạc từ quê hương họ tới Mĩ.

Đoạn cuối nói rằng người ta thật khó biết tên của những người đã khơi nguồn cho truyền thống âm nhạc này ở Mĩ. Do đó, đáp án đúng phải là B. it is hard to exactly recognize the people who started the American musical tradition: Thật khó để xác định chính xác những người khởi đầu cho truyền thống âm nhạc ở Mĩ.

31 tháng 8 2018

Đáp án B.

Key words: main idea of the passage.

Trong đoạn 1, 2 tác giả nêu ra rằng âm nhạc Mĩ khởi nguồn từ những người Mĩ gốc Phi; nhưng không ai bận tâm ghi chép về những người đã mang âm nhạc từ quê hương họ tới Mĩ.

Đoạn cuối nói rằng người ta thật khó biết tên của những người đã khơi nguồn cho truyền thống âm nhạc này ở Mĩ. Do đó, đáp án đúng phải là B. it is hard to exactly recognize the people who started the American musical tradition: Thật khó để xác định chính xác những người khởi đầu cho truyền thống âm nhạc ở Mĩ.

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   22  to  26A.   Read the passage carefully, then choose the correct answer.The ruined temples of Angkor are perhaps one of the mast impressive Seven Wonders of the World. Located in modern day Cambodia near Lake TonIe Sap, the largest freshwater lake in Asia, Angkor was the seat of power for the Khmer Empire from the ninth to the...
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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   22  to  26

A.   Read the passage carefully, then choose the correct answer.

The ruined temples of Angkor are perhaps one of the mast impressive Seven Wonders of the World. Located in modern day Cambodia near Lake TonIe Sap, the largest freshwater lake in Asia, Angkor was the seat of power for the Khmer Empire from the ninth to the fifteenth century. The ruins of Angkor are documented as same .of the mast impressive ones in the world, rivaling the pyramids of Giza in Egypt. Why this mighty civilization died out is a question that archeologists are now only beginning to ponder. The answer, it turns out, may be linked with the availability of fresh water.

One possible explanation far the downfall of the Khmer Empire has to do with the inhabitants' irrigation system. The temple and palaces of Angkor were constructed around a series of artificial reservoirs and canals which were annually flooded to capacity by the Mekong River. Once filled, they were used to irrigate the surrounding rice patties and farmland during the course of the year. Farmers were completely dependent upon the water for their crucial rice crop. Without consistent irrigation, the farmers would have been unable to maintain functional crop production.

Scientists speculate that toward the end of the Khmer Empire the hydraulic systems of the reservoirs and canals broke down. The construction of hundreds of sandstone temples and palaces required an enormous amount of physical labor. In addition, as the capital of the Khmer Empire, Angkor contained upwards of one hundred thousand people who resided in and around Angkor. In order to feed so many people, the local farmers were driven to grow food quicker and more efficiently. After centuries of continual use, the irrigation system was pushed beyond its capacity. Soil erosion, nutrient depletion, and the loss of water led to decrease in the food supply. With less food available, the people of Angkor slowly began to migrate to other parts of Cambodia thus leaving the marvelous city of Angkor to be swallowed by the jungle. Therefore, it is speculated that the Khmer Empire may have fallen victim to its own decrepit infrastructure.

22. What is the passage mainly about?

A. Modern day agricultural procedures in Cambodia.

B. A possible explanation for the, decline of a civilization.

C. The essential role water plays in farming.

D. Religious temples of the ancient Khmer Empire.

23. The passage preceding the passage most likely discusses ______.

A. architecture of ancient Asian civilization

B. religious practices of the people of Angkor

C. the form of government practiced by the Khmer Empire

D. the other six wonders of the world

24. According to the passage, Lake Tonle Sap in Cambodia ______.

A. is an enormous fresh body of water in Asia

B. was unable to supply enough fish for the people of Angkor

C. became polluted due to a population explosion

D. is one of the Seven Wonders of the World

25. Why does the author mention the hydraulic systems of the reservoirs?

A. They supplied irrigation from the Indian Ocean.

B. They became non-functional due to overuse.

C. They were destroyed by nearby warrior tribes.

D. They helped transport the sandstones for constructing temples.

26. It can be inferred from the passage that the inhabitants of the Khmer Empire ______.

A. were intentionally starved by the farmers

B. lost their food source due to excess rainfall

C. supplemented their diets with 'meat hunted in the nearby jungles

D. depended upon rice as their main source of food

27. All the following are mentioned as events that can affect food supply EXCEPT.

A. erosion of soil                                       B. contamination of soil

C. reduction of nutrients                            D. loss of water supply

 

2
16 tháng 4 2022

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   22  to  26

A.   Read the passage carefully, then choose the correct answer.

The ruined temples of Angkor are perhaps one of the mast impressive Seven Wonders of the World. Located in modern day Cambodia near Lake TonIe Sap, the largest freshwater lake in Asia, Angkor was the seat of power for the Khmer Empire from the ninth to the fifteenth century. The ruins of Angkor are documented as same .of the mast impressive ones in the world, rivaling the pyramids of Giza in Egypt. Why this mighty civilization died out is a question that archeologists are now only beginning to ponder. The answer, it turns out, may be linked with the availability of fresh water.

One possible explanation far the downfall of the Khmer Empire has to do with the inhabitants' irrigation system. The temple and palaces of Angkor were constructed around a series of artificial reservoirs and canals which were annually flooded to capacity by the Mekong River. Once filled, they were used to irrigate the surrounding rice patties and farmland during the course of the year. Farmers were completely dependent upon the water for their crucial rice crop. Without consistent irrigation, the farmers would have been unable to maintain functional crop production.

Scientists speculate that toward the end of the Khmer Empire the hydraulic systems of the reservoirs and canals broke down. The construction of hundreds of sandstone temples and palaces required an enormous amount of physical labor. In addition, as the capital of the Khmer Empire, Angkor contained upwards of one hundred thousand people who resided in and around Angkor. In order to feed so many people, the local farmers were driven to grow food quicker and more efficiently. After centuries of continual use, the irrigation system was pushed beyond its capacity. Soil erosion, nutrient depletion, and the loss of water led to decrease in the food supply. With less food available, the people of Angkor slowly began to migrate to other parts of Cambodia thus leaving the marvelous city of Angkor to be swallowed by the jungle. Therefore, it is speculated that the Khmer Empire may have fallen victim to its own decrepit infrastructure.

22. What is the passage mainly about?

A. Modern day agricultural procedures in Cambodia.

B. A possible explanation for the, decline of a civilization.

C. The essential role water plays in farming.

D. Religious temples of the ancient Khmer Empire.

23. The passage preceding the passage most likely discusses ______.

A. architecture of ancient Asian civilization

B. religious practices of the people of Angkor

C. the form of government practiced by the Khmer Empire

D. the other six wonders of the world

24. According to the passage, Lake Tonle Sap in Cambodia ______.

A. is an enormous fresh body of water in Asia

B. was unable to supply enough fish for the people of Angkor

C. became polluted due to a population explosion

D. is one of the Seven Wonders of the World

25. Why does the author mention the hydraulic systems of the reservoirs?

A. They supplied irrigation from the Indian Ocean.

B. They became non-functional due to overuse.

C. They were destroyed by nearby warrior tribes.

D. They helped transport the sandstones for constructing temples.

26. It can be inferred from the passage that the inhabitants of the Khmer Empire ______.

A. were intentionally starved by the farmers

B. lost their food source due to excess rainfall

C. supplemented their diets with 'meat hunted in the nearby jungles

D. depended upon rice as their main source of food

27. All the following are mentioned as events that can affect food supply EXCEPT.

A. erosion of soil                                       B. contamination of soil

C. reduction of nutrients                            D. loss of water supply

16 tháng 4 2022

22-b 23-d 24-a 25-b 26-d 27-b

2 tháng 8 2017

Đáp án: A

Giải thích: Đọc câu kế cuối đoạn thứ 3 có thể thấy từ them dùng để thay thế cho từ slang phrases (những cụm từ lóng).

6 tháng 1 2017

Đáp án C.

Key words: Scott Joplin, Bessie Smith.

Clue: “Many musicians today credit earlier musicians such as Scott Joplin or Bessie Smith with inspiring their music”: Nhiều nhạc sĩ ngày nay ghi nhận những cái tên đi trước như Scott Joplin hay Bessie Smith vì những nghệ sĩ này đã truyền cảm hứng sáng tác cho họ.

Vậy đáp án đúng phải là C. artists who inspired many musicians today.