K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

18 tháng 5 2022

it is essential that they ____ of the news
A. were heard
B. be heard
C. would be heard
D. will be heard

18 tháng 5 2022

B

1 where ................... you go if you have a car ? a will b are c would d were 2 you will fail the exam , ...........................you study harder a as b if c unless d although 3 if i ............................ a bird , i would be a dove a are b were c am d is 4 if today .............................sunday , we .......................to the beach a is / would go b were / would go c will be / will go d were / will go 5 if it .................... this morning , i will not to out a rain b...
Đọc tiếp

1 where ................... you go if you have a car ? a will b are c would d were 2 you will fail the exam , ...........................you study harder a as b if c unless d although 3 if i ............................ a bird , i would be a dove a are b were c am d is 4 if today .............................sunday , we .......................to the beach a is / would go b were / would go c will be / will go d were / will go 5 if it .................... this morning , i will not to out a rain b rained c rains d raining 6 nobody hates you ! it is all in your ......................................... a imagine b imaginary c imagining d imagination 7 i am poor , so i can not buy a car a if i am rich , i can buy a car b if i were rich , i can buy a car c if i were rich , i could buy a car d if i were rich , i will buy a car 8 water these plants or they will die a if you did not water these plants , they will die b if you water these plants , they will die c if i do not water these plants , they will die d if you are watering these plants , they will die 9 where is lan ? _parhaps she is working a she may be working b she can be working c she must be working d she will be working 10 nam will probalby be there a nam is here b nam might be there c she must be there d nam might not be there 11 the house ............................. shakespeare was born is open to the public a where b which c that d when 1 2 a .......................... was a person who went through city streets shouted the latest news a town crier b magician c singer d clown 13 if he spoke english more slowly , she ......................... so many mistakes a will not make b would not make c did not make d made

1
12 tháng 5 2017

1 where ................... you go if you have a car ? a will b are c would d were

2 you will fail the exam , ...........................you study harder a as b if c unless d although

3 if i ............................ a bird , i would be a dove a are b were c am d is

4 if today .............................sunday , we .......................to the beach a is / would go b were / would go c will be / will go d were / will go

5 if it .................... this morning , i will not to out a rain b rained c rains d raining

6 nobody hates you ! it is all in your ......................................... a imagine b imaginary c imagining d imagination

7 i am poor , so i can not buy a car a if i am rich , i can buy a car b if i were rich , i can buy a car c if i were rich , i could buy a car d if i were rich , i will buy a car

8 water these plants or they will die a if you did not water these plants , they will die b if you water these plants , they will die c if i do not water these plants , they will die d if you are watering these plants , they will die

9 where is lan ? _parhaps she is working a she may be working b she can be working c she must be working d she will be working 10 nam will probalby be there a nam is here b nam might be there c she must be there d nam might not be there

11 the house ............................. shakespeare was born is open to the public a where b which c that d when

1 2 a .......................... was a person who went through city streets shouted the latest news a town crier b magician c singer d clown

13 if he spoke english more slowly , she ......................... so many mistakes a will not make b would not make c did not make d made

1. Fortunately, I .... working alone otherwise I would have got really bored at the night shift. A) was supposed to B) was to C) was used to D) would E) used to 2. I don't think it was a good idea to intervene, instead, you .... your child to abandon the habit of thumb-sucking gradually, all by himself. A) have allowed B) had allowed C) must have allowed D) were able to allow E) could have allowed 3. After the voyaging ship was wrecked during a storm at sea, unfortunately, only two of the men...
Đọc tiếp

1. Fortunately, I .... working alone otherwise I would have got really bored at the night shift.
A) was supposed to
B) was to
C) was used to
D) would
E) used to

2. I don't think it was a good idea to intervene, instead, you .... your child to abandon the habit of thumb-sucking gradually, all by himself.
A) have allowed
B) had allowed
C) must have allowed
D) were able to allow
E) could have allowed

3. After the voyaging ship was wrecked during a storm at sea, unfortunately, only two of the men on board .... swim to the small island nearby.
A) might
B) were supposed to
C) could
D) were able to
E) had to

4. I don't know why she didn't ask me how to do it as I ---- her.
A) must have helped
B) could have helped
C) might help
D) should have helped
E) could help

5. Martin ---- my tennis racket without asking my permission. I got really angry with him.
A) needn't have taken
B) must not have taken
C) shouldn't have taken
D) didn't need to taken
E) might not have taken

6. I don't know why Peter is so late; do you think he ---- lost coming here?
A) may get
B) could get
C) must have got
D) might have got
E) was to have got

7. What ---- to Phil? He said he ---- here at eight o'clock.
A) might have happened / will be
B) should have happened / has been
C) may happen / will have been
D) would happen / is
E) can have happened / would be

8. One of the US national security advisers ---- there ---- better intelligence sharing before the September 11 attacks.
A) had acknowledged / can be
B) acknowledges / might be
C) has acknowledged / could have been
D) acknowledged / must be
E) would acknowledge / will have been

9. We all think that Maria ---- an interesting person to meet as we ---- a lot of stories about her so far.
A) is / had heard
B) can be / heard
C) might have been / hear
D) would be / have heard
E) will be / will have heard

10. As a young woman who had never given birth before, she ---- what the experience of childbirth ---- like.
A) doesn't know / will be
B) may not know / is
C) must not have known / will be
D) may not know / would be
E) couldn't have known / would be

2
18 tháng 10 2017

1. Fortunately, I .... working alone otherwise I would have got really bored at the night shift.
A) was supposed to
B) was to
C) was used to
D) would
E) used to

2. I don't think it was a good idea to intervene, instead, you .... your child to abandon the habit of thumb-sucking gradually, all by himself.
A) have allowed
B) had allowed
C) must have allowed
D) were able to allow
E) could have allowed

3. After the voyaging ship was wrecked during a storm at sea, unfortunately, only two of the men on board .... swim to the small island nearby.
A) might
B) were supposed to
C) could
D) were able to
E) had to

4. I don't know why she didn't ask me how to do it as I ---- her.
A) must have helped
B) could have helped
C) might help
D) should have helped
E) could help

5. Martin ---- my tennis racket without asking my permission. I got really angry with him.
A) needn't have taken
B) must not have taken
C) shouldn't have taken
D) didn't need to taken
E) might not have taken

6. I don't know why Peter is so late; do you think he ---- lost coming here?
A) may get
B) could get
C) must have got
D) might have got
E) was to have got

7. What ---- to Phil? He said he ---- here at eight o'clock.
A) might have happened / will be
B) should have happened / has been
C) may happen / will have been
D) would happen / is
E) can have happened / would be

8. One of the US national security advisers ---- there ---- better intelligence sharing before the September 11 attacks.
A) had acknowledged / can be
B) acknowledges / might be
C) has acknowledged / could have been
D) acknowledged / must be
E) would acknowledge / will have been

9. We all think that Maria ---- an interesting person to meet as we ---- a lot of stories about her so far.
A) is / had heard
B) can be / heard
C) might have been / hear
D) would be / have heard
E) will be / will have heard

10. As a young woman who had never given birth before, she ---- what the experience of childbirth ---- like.
A) doesn't know / will be
B) may not know / is
C) must not have known / will be
D) may not know / would be
E) couldn't have known / would be

19 tháng 10 2017

1. Fortunately, I .... working alone otherwise I would have got really bored at the night shift.
A. was supposed to
B. was to
C. was used to
D. would
E. used to

2. I don't think it was a good idea to intervene, instead, you .... your child to abandon the habit of thumb-sucking gradually, all by himself.
A. have allowed
B. had allowed
C. must have allowed
D. were able to allow
E. could have allowed

3. After the voyaging ship was wrecked during a storm at sea, unfortunately, only two of the men on board .... swim to the small island nearby.
A. might
B. were supposed to
C. could
D. were able to
E. had to

4. I don't know why she didn't ask me how to do it as I ---- her.
A. must have helped
B. could have helped
C. might help
D. should have helped
E. could help

5. Martin ---- my tennis racket without asking my permission. I got really angry with him.
A. needn't have taken
B. must not have taken
C. shouldn't have taken
D. didn't need to taken
E. might not have taken

6. I don't know why Peter is so late; do you think he ---- lost coming here?
A. may get
B. could get
C. must have got
D. might have got
E. was to have got

7. What ---- to Phil? He said he ---- here at eight o'clock.
A. might have happened / will be
B. should have happened / has been
C. may happen / will have been
D. would happen / is
E. can have happened / would be

8. One of the US national security advisers ---- there ---- better intelligence sharing before the September 11 attacks.
A. had acknowledged / can be
B. acknowledges / might be
C. has acknowledged / could have been
D. acknowledged / must be
E. would acknowledge / will have been

9. We all think that Maria ---- an interesting person to meet as we ---- a lot of stories about her so far.
A. is / had heard
B. can be / heard
C. might have been / hear
D. would be / have heard
E. will be / will have heard

10. As a young woman who had never given birth before, she ---- what the experience of childbirth ---- like.
A. doesn't know / will be
B. may not know / is
C. must not have known / will be
D. may not know / would be
E. couldn't have known / would be

It was not ... to finish that work before 5 o'clock ( expected, expecting,expectative, expectation) These were the day ...we were very happy ( that , of wich, about wich, when) She remembered the correct address only....she had posted the letter ( since, afterward, following, after) ... from bill , all the student said they would go ( except, only, apart, separate) The smaller the room is , the ... furniture is needs ( fewer, smaller, more,less) How can I knows ... book is yours ? They are...
Đọc tiếp

It was not ... to finish that work before 5 o'clock ( expected, expecting,expectative, expectation)

These were the day ...we were very happy ( that , of wich, about wich, when)

She remembered the correct address only....she had posted the letter ( since, afterward, following, after)

... from bill , all the student said they would go ( except, only, apart, separate)

The smaller the room is , the ... furniture is needs ( fewer, smaller, more,less)

How can I knows ... book is yours ? They are alike ( which, what, that the)

Nobody knows what the ....of the explosion was ( source, cause,reation, reason)

Either you or your friend ..on charge today ( are,is, were,was)

It looks ... it is going to rain ( as,as like,as if ,if)

Babies have to learn how to ... before they can walk ( crawl , creep , strike,stroll)

Although he shouted , he could not make his voice...( Hear,to hear , heard,to be heard)

I read a book about Picasso ,... Spanish painter ( is a , that is,who is , a)

We have ...of time to catch the bus so there no need to rush ( a great deal, enough, very much , a plenty)

He wants you to ...a good hotel ( introduce, direct , recommend, tell)

The more ...we walk , the longer it will take us to get home ( slowest, slower , slowly, slow)

1
10 tháng 6 2019

It was not ... to finish that work before 5 o'clock ( expected, expecting,expectative, expectation)

These were the day ...we were very happy ( that , of wich, about wich, when)

She remembered the correct address only....she had posted the letter ( since, afterward, following, after)

... from bill , all the student said they would go ( except, only, apart, separate)

The smaller the room is , the ... furniture is needs ( fewer, smaller, more,less)

How can I knows ... book is yours ? They are alike ( which, what, that the)

Nobody knows what the ....of the explosion was ( source, cause,reation, reason)

Either you or your friend ..on charge today ( are,is, were,was)

It looks ... it is going to rain ( as,as like,as if ,if)

Babies have to learn how to ... before they can walk ( crawl , creep , strike,stroll)

Although he shouted , he could not make his voice...( Hear,to hear , heard,to be heard)

I read a book about Picasso ,... Spanish painter ( is a , that is,who is , a)

We have ...of time to catch the bus so there no need to rush ( a great deal, enough, very much , a plenty)

He wants you to ...a good hotel ( introduce, direct , recommend, tell)

The more ...we walk , the longer it will take us to get home ( slowest, slower , slowly, slow)

Rewrite as directed1. It would be nice to be able to fly.                     -> I wish …………………………………………….2. I wish I hadn’t heard that.-> I’d rather you…………………………………3. Everyone wished they had listened more carefully to the lecture.-> Everyone regretted ………………………………………………………….4. Unfortunately I’ve got to work late tonight.-> I wish ……..5. Is it better for me to leave?-> Would you ………..6. It’s a pity I can’t borrow your car.-> I wish you would…………7. We really must discuss this again.-> It’s...
Đọc tiếp

Rewrite as directed

1. It would be nice to be able to fly.                     

-> I wish …………………………………………….

2. I wish I hadn’t heard that.

-> I’d rather you…………………………………

3. Everyone wished they had listened more carefully to the lecture.

-> Everyone regretted ………………………………………………………….

4. Unfortunately I’ve got to work late tonight.

-> I wish ……..

5. Is it better for me to leave?

-> Would you ………..

6. It’s a pity I can’t borrow your car.

-> I wish you would…………

7. We really must discuss this again.

-> It’s important that …………

8. It’s a pity you were driving so fast.

-> I wish you ………….

9. May the President live a long time.

-> Long ….

10. Jack prefers me not to say anything about the missing money.

-> Jack would rather ………..

0
Rewrite as directed1. It would be nice to be able to fly.                     -> I wish …………………………………………….2. I wish I hadn’t heard that.-> I’d rather you…………………………………3. Everyone wished they had listened more carefully to the lecture.-> Everyone regretted ………………………………………………………….4. Unfortunately I’ve got to work late tonight.-> I wish ……..5. Is it better for me to leave?-> Would you ………..6. It’s a pity I can’t borrow your car.-> I wish you would…………7. We really must discuss this again.-> It’s...
Đọc tiếp

Rewrite as directed

1. It would be nice to be able to fly.                     

-> I wish …………………………………………….

2. I wish I hadn’t heard that.

-> I’d rather you…………………………………

3. Everyone wished they had listened more carefully to the lecture.

-> Everyone regretted ………………………………………………………….

4. Unfortunately I’ve got to work late tonight.

-> I wish ……..

5. Is it better for me to leave?

-> Would you ………..

6. It’s a pity I can’t borrow your car.

-> I wish you would…………

7. We really must discuss this again.

-> It’s important that …………

8. It’s a pity you were driving so fast.

-> I wish you ………….

9. May the President live a long time.

-> Long ….

10. Jack prefers me not to say anything about the missing money.

-> Jack would rather ………..

1
25 tháng 8 2021

Rewrite as directed

1. It would be nice to be able to fly.                     

-> I wish …………………I could be able to fly ………………………….

2. I wish I hadn’t heard that.

-> I’d rather you…………… hadn'd told me that……………………

3. Everyone wished they had listened more carefully to the lecture.

-> Everyone regretted …………………not listening more carefully to lecture.……………………………………….

4. Unfortunately I’ve got to work late tonight.

-> I wish … i get to work early tonight…..

5. Is it better for me to leave?

-> Would you …sooner i left……..

6. It’s a pity I can’t borrow your car.

-> I wish you would……borrow your car.……

7. We really must discuss this again.

-> It’s important that ……we dicuss this again……

8. It’s a pity you were driving so fast.

-> I wish you ……hadn’t been driving so fast…….

9. May the President live a long time.

-> Long …live the president!....................

10. Jack prefers me not to say anything about the missing money.

-> Jack would rather …I didn’t say anything abiut the missing money……..

Rewrite as directed 1. It would be nice to be able to fly.                     -> I wish …………………………………………….2. I wish I hadn’t heard that.-> I’d rather you…………………………………3. Everyone wished they had listened more carefully to the lecture.-> Everyone regretted ………………………………………………………….4. Unfortunately I’ve got to work late tonight.-> I wish ……..5. Is it better for me to leave?-> Would you ………..6. It’s a pity I can’t borrow your car.-> I wish you would…………7. We really must discuss this again.-> It’s...
Đọc tiếp

Rewrite as directed

1. It would be nice to be able to fly.                     

-> I wish …………………………………………….

2. I wish I hadn’t heard that.

-> I’d rather you…………………………………

3. Everyone wished they had listened more carefully to the lecture.

-> Everyone regretted ………………………………………………………….

4. Unfortunately I’ve got to work late tonight.

-> I wish ……..

5. Is it better for me to leave?

-> Would you ………..

6. It’s a pity I can’t borrow your car.

-> I wish you would…………

7. We really must discuss this again.

-> It’s important that …………

8. It’s a pity you were driving so fast.

-> I wish you ………….

9. May the President live a long time.

-> Long ….

10. Jack prefers me not to say anything about the missing money.

-> Jack would rather ………..

0
Read the passage, and choose the best answer. Good manners are a treasure to the people who possess them, as well as to the community they live in. Manners are taught, learnt, and passed from generation to generation. Even hundreds of years ago, children were taught to behave responsibly. They learnt to respect seniority. When they passed an object to another person, they had to use both hands. When they entered a room, they had to bow and greet the oldest person first. Boys learnt to work hard...
Đọc tiếp

Read the passage, and choose the best answer.

 

Good manners are a treasure to the people who possess them, as well as to the community they live in. Manners are taught, learnt, and passed from generation to generation.

 

Even hundreds of years ago, children were taught to behave responsibly. They learnt to respect seniority. When they passed an object to another person, they had to use both hands. When they entered a room, they had to bow and greet the oldest person first. Boys learnt to work hard to support their families. Girls learnt to do housework, and to take care of others. Loyalty and honesty were highly appreciated. When they made a mistake, they would not let another person be punished for it. That would be cowardly and mean. They were taught that families were strong, and everybody should stick together in adversity. (tai họa, nghịch cảnh)

 

Fortunately, many of these values have been well preserved. They have contributed to making the unique Vietnamese culture, and strengthening our society.

The sentence: “When they made a mistake, they would not let another person be punished for it,” means they would _______________________.

A. deny their mistake

B. admit their mistake

C. keep it a secret

D. be punished

1
1 tháng 8 2018

Đáp án là B.

13 tháng 8 2017

A. Correct the following sentences if necessary by taking out the inappropriate word:

1, The dog must be let out of the garden.

2, When was America discovered by?

3, The staff was be given extra money for Christmas.

4, It is been believed that the President will tour the USA next year.

5, The reporst can be being completed tomorrow.

6, My cat got be hit by a car.

=> was

7, I heard him to say that he would quit his job.

=> said

8, Five hundred handbags will have been made by the end of the day.

=> at

9, The garden was covered with snow.

=> by

10, Who has been turned on the lights?

1. If people solve the problem of smoke from vehicles and factories, the air _____ pure and fresh. A. is B. was C. will be D. would be 2. If you post false information on the Internet, you _____fined. A. gets B. got C. would get D. will...
Đọc tiếp

1. If people solve the problem of smoke from vehicles and factories, the air _____ pure and fresh. A. is B. was C. will be D. would be 2. If you post false information on the Internet, you _____fined. A. gets B. got C. would get D. will get 3. I believe that if all the people _____ the government’s instructions, we ____COVID-19 from spreading. A. don’t follow/ will prevent B. followed/ will prevent C. follow/ would prevent D. follow/ will prevent 4. Do you think there would be less conflict in the world if all people _____ the same language? A. spoke B. speak C. had spoken D. will speak 5. If our schools are still closed because of the pandemic, we _____to study online. A. wouldn’t B. would try C. tried D. will try 6. If I ____you, I ____many subjects online instead of playing video games. A. was/ will study B. am/ will study C. were/ would study D. am/ would study 7. If people need more paper, more trees _____. A. will cut down B. cut down C. will be cut down D. are cutting down 8. My English is not good. If I ___ English well, I ___ able to get a good job in a foreign company. A. speak/ can be B. spoke / were C. speak/ were D. spoke/ would be 9. If everybody _____to the fight against COVID-19, we will win soon. A. contribute B. contributes C. are contributing D. is contributed 10. If people protect the forest, a lot of trees _____. A. will be preserved B. will preserve C. preserve D. would preserve 11. If you were me, what _____? A. you would do B. will you do C. do you do D. would you do 12. People don’t trust him because he tells lies. A. If he tells lies, people won’t trust him. B. If he didn’t tell lies, people would trust him. C. If he doesn’t tell lies, people will trust him. D. If he told lies, people wouldn’t trust him. 13. The government limits travel and close contact among people, so we can prevent COVID-19 from spreading. A. If the government didn’t limit travel and close contact among people, we couldn’t prevent COVID-19 from spreading. B. If the government doesn’t limit travel and close contact among people, we can prevent COVID-19 from spreading. C.If the government doesn’t limit travel and close contact among people, we could prevent COVID-19 from spreading. D. If the government limited travel and close contact among people, we couldn’t prevent COVID-19 from spreading. 14. Wear a face mask when you are with many people, or you will be at risk. A. If you wear a face mask when you are with many people, you will be at risk. B. If you don’t wear a face mask when you are with many people, you will be at risk. C. If you didn’t wear a face mask when you are with many people, you would be at risk. D. If you don’t wear a face mask when you are with many people, you would be at risk. 18. We/ should/ maintain/ personal space/ avoid/ crowds/ if/ we/ want/ be/ safe/ now. A. We should be maintained personal space and avoid crowds if we want to be safe now. B. We should maintain personal space and avoid crowds if we want to be safe now. C. We should maintain personal space and avoid crowds if we wanted to be safe now. D. We should maintain personal space to avoid crowds if we want be safe now. 19. Her English/ not/ be/ rusty/ she/ used/ more often. A. Her English wouldn’t be rusty if she uses it more often. B. Her English wouldn’t be rusty if she has used it more often. C. Her English wouldn’t be rusty if she is using it more often. D. Her English wouldn’t be rusty if she used it more often. 20. If people/ solve/ problem/ smoke from vehicles, the air/ be pure and fresh. A. If people solved the problem of smoke from vehicles, the air is pure and fresh. B. If people solve the problem of smoke from vehicles, the air was pure and fresh. C. If people solve the problem of smoke from vehicles, the air will be pure and fresh. D. If people solve the problem of smoke from vehicles, the air would be pure and fresh.
1
4 tháng 4 2020

1. If people solve the problem of smoke from vehicles and factories, the air _____ pure and fresh.

A. is B. was C. will be D. would be

2. If you post false information on the Internet, you _____fined.

A. gets B. got C. would get D. will get

3. I believe that if all the people _____ the government’s instructions, we ____COVID-19 from spreading.

A. don’t follow/ will prevent

B. followed/ will prevent

C. follow/ would prevent

D. follow/ will prevent

4. Do you think there would be less conflict in the world if all people _____ the same language?

A. spoke B. speak C. had spoken D. will speak

5. If our schools are still closed because of the pandemic, we _____to study online.

A. wouldn’t B. would try C. tried D. will try

6. If I ____you, I ____many subjects online instead of playing video games.

A. was/ will study B. am/ will study C. were/ would study D. am/ would study

7. If people need more paper, more trees _____.

A. will cut down B. cut down C. will be cut down D. are cutting down

8. My English is not good. If I ___ English well, I ___ able to get a good job in a foreign company.

A. speak/ can be B. spoke / were C. speak/ were D. spoke/ would be

9. If everybody _____to the fight against COVID-19, we will win soon.

A. contribute B. contributes C. are contributing D. is contributed

10. If people protect the forest, a lot of trees _____.

A. will be preserved B. will preserve C. preserve D. would preserve

11. If you were me, what _____?

A. you would do B. will you do C. do you do D. would you do

12. People don’t trust him because he tells lies.

A. If he tells lies, people won’t trust him.

B. If he didn’t tell lies, people would trust him.

C. If he doesn’t tell lies, people will trust him.

D. If he told lies, people wouldn’t trust him.

13. The government limits travel and close contact among people, so we can prevent COVID-19 from spreading.

A. If the government didn’t limit travel and close contact among people, we couldn’t prevent COVID-19 from spreading.

B. If the government doesn’t limit travel and close contact among people, we can prevent COVID-19 from spreading.

C.If the government doesn’t limit travel and close contact among people, we could prevent COVID-19 from spreading.

D. If the government limited travel and close contact among people, we couldn’t prevent COVID-19 from spreading.

14. Wear a face mask when you are with many people, or you will be at risk.

A. If you wear a face mask when you are with many people, you will be at risk.

B. If you don’t wear a face mask when you are with many people, you will be at risk.

C. If you didn’t wear a face mask when you are with many people, you would be at risk.

D. If you don’t wear a face mask when you are with many people, you would be at risk.

18. We/ should/ maintain/ personal space/ avoid/ crowds/ if/ we/ want/ be/ safe/ now.

A. We should be maintained personal space and avoid crowds if we want to be safe now.

B. We should maintain personal space and avoid crowds if we want to be safe now.

C. We should maintain personal space and avoid crowds if we wanted to be safe now.

D. We should maintain personal space to avoid crowds if we want be safe now.

19. Her English/ not/ be/ rusty/ she/ used/ more often.

A. Her English wouldn’t be rusty if she uses it more often.

B. Her English wouldn’t be rusty if she has used it more often.

C. Her English wouldn’t be rusty if she is using it more often.

D. Her English wouldn’t be rusty if she used it more often.

20. If people/ solve/ problem/ smoke from vehicles, the air/ be pure and fresh.

A. If people solved the problem of smoke from vehicles, the air is pure and fresh.

B. If people solve the problem of smoke from vehicles, the air was pure and fresh.

C. If people solve the problem of smoke from vehicles, the air will be pure and fresh.

D. If people solve the problem of smoke from vehicles, the air would be pure and fresh.