on the mine, it wouldn't have exploded.
21. In my experiments, the liquid is cooled to 32°F. It always freezes.
A. If you cool the liquid to 32 degrees, it froze.
B. If you cooled the liquid to 32 degrees, it would freeze.
C. If you cool the liquid to 32 degrees, it will freeze.
D. If you had cooled the liquid to 32 degrees, it would have frozen.
22. It may rain this afternoon. I hope it doesn't because I don't want the match to be cancelled.
A. If it rains, the match is cancelled.
B. If it rains, the match will be cancelled.
C. if it rained, the match would be cancelled.
23. Unfortunately, I don't know Philosophy, so I can't answer your question.
A. If I know Philosophy, I can answer your question.
B. If I know Philosophy, I will be able to answer your question.
C. If I knew Philosophy, I would be able to answer your question.
D. If I had known Philosophy, I would have been able to answer your question.
24.
there are some more ideas, we can end the meeting now.
A. If
B. As if
C. Unless
25. If he
with us now, he
A. is / can enjoy B. was/will enjoy
26. If they had searched more carefully, they...the
A. will find
B. would find
27. If I had got up early, I
A. have
B.I had
28. I cannot buy a new computer
A. if
B. even if
D. If it had rained, the match would have been cancelled.
the beauty of nature of the National Park.
C. has been / would enjoy
watch sooner.
C. found
to have breakfast now.
29. Most people you meet will be polite to you
A. if you are polite to them
C. unless you are polite to them
C. would have
I save enough money.
C. unless
D. as if
B. if you will be polite to them
D. if you were polite to thom
D. In case
D. were / could enjoy
D. would have found
D. would have had