=>
11. A on
12. C : sạch
13. C : mặc dù
14. B seasonal
15. A lanterns

C/
1. amount
2. As
3. on
4. small
5. what
6. balance
7. fossil
8. lowering

D/
1. Coal is more expensive and polluting than natural gas.
2. Will fossil fuels replaced by solar and win within 20 years?
3. I have not visited Yaly hydroelectric power plant before.
4. Flying cars will be used to travel across the globe some day.

11. A 

12. C

13. C 

14. B

15. A 

C,
1. C                

2. A
3. C                             

4. A
5. B                                 

6. D
7. A                          

8. B

D,
1.

Coal is more expensive and polluting than natural gas.
2.

Will fossil fuels replaced by solar and win within 20 years?
3.

I have not visited Yaly hydroelectric power plant before.
4.

Flying cars will be used to travel across the globe some day.