16. I know a number of occasions____ people died from water pollution.
A. how
B. as
C. when
D. where
17. Dirty water must not be _____ with drinking water.
A. joined
B. linked
C. mixed
D. bined
18. The main road through the city was blocked for three hours today after an accident____ two buses.
A. containing
B. connecting
C. including
D. involving
19. Will you go to the meeting ____ visiting the museum please?
A. or
B. and
C. to
D. instead of
20. Smith is to study medicine as soon as he ____ military service.
A. will finish
B. has finished
C. finish
D. would finish
21. If a metal bar is heated，the greater the heat ____，the larger the expansion.
A. applied
B. being applied
C. applying
D. is applied
22. They did not discover until later____ the car had been destroyed.
A. as
B. than
C. which
D. that
23. He has already made up his mind. It's no use ____ him.
A. try to persuade
B. trying to persuade
C. to try to persuade
D. to try persuading
24. It is much easier to talk about social change than____.
A. to bring it about
B. to bring it on
C. to bring it up
D. to bring it out
25. ____ seems easy in theory seems difficult in practice.
A. That
B. With
C. What
D. It
26. The house is dark;the Browns_____ to bed.
A. may go
B. should go
C. should have gone
D. must have gone
27. This is a mistake which is typical ____ beginners.
A. for B. of
C. to D. with
28. There may be，somewhere outside the solar system，intelligent life ____ messages to us.
A. sends
B. sent
C. sending
D. has sent
29. Please be sure to telephone me the next time you____.
A. will
B. would
C. shall
D. \
30. All the machines____ by the end of the following week.
A. were repaired
B. will be repaired
C. have been repaired
D. will have been repaired
