=>

I/

1. C

2. B : prevent from 

3. B ( rút gọn mđqh) 

4. D

5. A : nhưng 

6. B

7. B

8. D

9. D : this is the first time + HTHT

10. B

11. A

12. B : in order to + V

II/

1. Kept 

2. Opening / is 

3. Won't catch / don't hurry

4. Looks / was built 

5. Inviting 

III/

1. Mixture

2. Natural

3. Peaceful 

4. Slowly 

5. Flights

6. Dangerous 

IV/

1. Milk is used for making butter and cheese. 

2. This hard problem won't be solved. 

3. Are my questions answered? 

4. Jeans can't be worn at school by us. 

I.

1.C

2.B

3.B

4.D

5.A

6.B

7.B

8.D

9.D

10.B

11.A

12.B

II.

1.kept

2.opening/is

3.won't catch/don't hurry

4.looks/was built

5.inviting

III.

1.mixture

2.natural

3.peaceful

4.slowly

5.flights

6.dangerous

IV.

1.Milk is used for making butter and cheese by him.

2.This hard problem won't be solved.

3.Are my question answered?

4.Jeans can't be worn at school.