1. d. for

2. c. for

3. d. for - of

4. b. reduce

5. a. energy - saving

6. a. homestead

7. d. Finally

8. b. very large

9. c. an electrician

10. a. why not

B. 

11. appliances

12. producer

13. efficiency

14. consumption

15. effectively

III. A. 

1. d. take

2. a. give up

3. a. look after

4. b. off

5. d. therefore

6. c. contacting

7. b. energy enough

8. b. or

9. a. come

10. d. and

11. b. however

12. c. because

13. d. use - can save

14. b. pick it up

15. c. you should finish

B.

16. D. wash→ washing

17. D. wake up you→ wake you up

18. B. would get→ will get

19. B. to go→ went

20. C. reach→ reaches

4.The world's energy resources is limited so we should use them economically.

5. The country could face an energy crisis if demand continued to rise.

6. You can't borrow my dictionary unless you bring it back on Monday.

7. Solar domestic heating systems are economical to use but the cost of installation is very high.

8. Solar pannels are placed on the roof of a house  and the Sun' energy is used to heat water.

9. He is a good teacher, however, I don't agree with a lot of his teaching methods.

10. We'd better not waste water or we won't have enough to drink sooner or later.