14. About _______ of the energy is absorbed by the atmosphere of the earth.

A. nine-ten

B. nine-tenth

C. nine-tenths

D. ninth-ten

15. David helps his mother with her housework every Saturday for about _______.

A. one and half hours

B. a half and an hour

C. an hour and half

D. one and a half hours

16. Not many people realize this， ______ it is quite true.

A. but

B. however

C. so

D. that

17. -Can I help you? -Well， I’m afraid the box is too heavy for you， ____ thank you all the same.

A. and

B. so

C. or

D. but

18. I don’t know her address， ______ I can’t write to her.

A. but

B. or

C. so

D. since

19. She hardly ever goes to ______ the theatre. A. neither the cinema or

B. neither the cinema nor

C. either the cinema nor

D. either the cinema or

20. Try your best ______ you’ll certainly succeed this time.

A. so

B. and

C. or

D. for

21. She remained silent， ______ her heart was heavy and her spirit low.

A. so

B. though

C. for

D. therefore

22. He talked at the top of his voice， ______ he drew nobody’s attention.

A. yet

B. instead

C. so

D. though

23. Watch your step， ______ you might fall into the water.

A. or

B. and

C. unless

D. but

24. He came to the party， ______ he hadn’t been invited.

A. in case

B. in spite of

C. even

D. although

25. ______ hearing the good news， they jumped with joy.

A. For

B. To

C. On

D. At