31. He came to help us_____ he had plenty of work to do.

　 A. as　　　　　　 B. while　　　　　　 C. although　　　 D. whenever

30. It’s a pity Lao Wang isn’t here. If he______ we would be happier.

　 A. came 　　　　　B. had come　　　　 C. has come　　　 D. comes

29. _______ slowly he might have understood you.

　 A. If you spoke　　　　　　　　　　　 B. Speak

　 C. Had you spoken　　　　　　　　　　 D. If you should speak

28. If the sun_______ rise tomorrow, what would happen?

　 A. cannot　　　　 B. would not　　　 C. should not　　 　D. does not

27. I wonder if he______ us, but I think if he______ us, we’ll be able to complete the task ahead of time.

　 A. helps, helps　　　　　　　　　 B. will help, helps

　 C. is helping, is helping　　　　　　 D. would help, has helped

26. She made a note of it______ she might forget.

　 A. so that　　　　 B. in order that　　 C. if　　　 D. in case

25. You will not succeed unless you_______ harder.

　 A. will work 　　　B. won’t work　　 C. work　　　　 D. don’t work

24. Five minutes earlier, ______ we could have caught the last train.

　 A. or　　　　　　 B. but　　　　　 C. and　　　　　 D. so

23. What______ to do if he needs the book?

　 A. has he 　　　　B. he has　　　　 C. will he have　 D. he will have

22. We’re not going to operate on him________ it is absolutely necessary.

　 A. if　　　　　　 B. unless　　　　 C. as long as　　 D. so far as