1. The United States is composed of fifty states, two of _____ are separated from the others by land or water.

　　A. them B. that

　　C. which D. those

　　2. They did not discover until later _____ the car had been destroyed.

　　A. as B. than

　　C. which D. that

　　3. They overcame all the difficulties and fulfilled the plan ten days ahead of schedule, _____ was something we had not expected.

　　A. that B. this

　　C. it D. which

　　4. That’s the reason _____ Ann could not do her part of the job.

　　A. that B. of

　　C. because D. why

　　5. The company official _____ I thought would be fired received a raise.

　　A. whom B. whoever

　　C. who D. of whom

　　6. In 1990 he caught a serious illness from _____ effects he still suffers.

　　A. that B. which

　　C. what D. whose

　　7. His brother had become a teacher, _____ he wanted to be.

　　A. who B. what

　　C. which D. that

　　8. My vacation begins next Tuesday, _____ I will leave for Flofida.

　　A. which B. that

　　C. while D. when

　　9. He has made another wonderful discovery, _____ of great importance to science.

　　A. which I think it is B. of which I think is

　　C. I think which is D. which I think is

　　10. I decided to buy a car because we had sold _____ we had in England before leaving.

　　A. that B. the other

　　C.which D. the one

　　11. The investigation, _____ will soon be published, was made by John.

　　A. at which the results B. the results on which

　　C. whose results D. at whose results

　　12. Crude oil is refined in a refinery, _____ makes it possible to get many grades of oils for different uses.

　　A. as B. that

　　C. this D. which

　　13. I am sure that _____ you said is wrong.

　　A. which B. all

　　C. this D. how

　　14. He arrived late for the tea party, _____ made us all very disappointed.

　　A. which B. this

　　C. it D. that

　　15. The people at the party were worried about John because no one was aware _____ he had gone.

　　A. where that B. where

　　C. of the place where D. the place

　　16. Is there anyone you can think of _____ may know her address?

　　A. which B. that

　　C. who D. what

　　17. Perhaps the day will come _____ people will live 150 years.

　　A. which B. that

　　C. who D. what

　　18. It was raining, _____ was a pity.

　　A. what B. that

　　C. as D. which

　　19. This is the reason _____ an aeroplane can’t fly in space.

　　A. which B. why

　　C. where D. for that

　　20. We’ve tested three hundred types of boot, _____ completely waterproof.

　　A. no of which B. none of which

　　C. some of that D. neither of which