12.　 He has made a wonderful discovery, _______ of great importance to science.

A. which I think is　 B. which do I think is　

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

11.　 She may have missed her train, in ______ case she won’t arrive for another hour.

A. what　 B. that　 C. which　 D. this

10.　 He arrived in New York in 1896, _______, some time later, he became a writer.

A. when　 B. where　 C. that　 D. which

9.　　 I’ll never forget the years ______ I lived in the country with the farmers ______ has a great effect on my life.

A. that; which　 B. when; which　 C. which; that　 D. when; who

8.　　 We traveled together as far as Chicago, ______ we said goodbye to each other.

A. which　 B. when　 C. why　 D. where

7.　　 We had to delay the party till next week, ______ we should have something important to do.　　　　　　　　 A. when　 B. which　 C. at which　 D. in that

6.　　 Mr Johnson’s son, ______ lives in Chicago, is a doctor.

A. who　 B. whom　 C. that　 D. which

5.　　 When lost in work, ____ he often was, he would forget all about eating and sleeping.　 A. what　　 B so　 C. just like　 D. as

4.　　 There’s still much ______ can be improved about it.

A. which　 B. that　 C. if　　 D. what

3.　　 The fence in our garden, ______ my father built many years ago, has lasted for a long time.　　　　　　　　　 A. that　 B. which　 C. what　 D. where