9.　　　 We have kept in t_________ by letter for many years.

8.　　　 I didn’t begin to learn a________ maths until I went to college.

7.　　　 When I arrived at the hotel the r_________ told me which room to live in.

6.　　　 An earthquakes is a natural d_________.

5.　　　 He went there for f_______ , not on business.

4.　　　 The dogs ________ (吓)the thief away.

3.　　　 The boy _______ (打中) the other boy and was naturally punished by the headmaster.

2.　　　 The party was _________ (主办)by Mrs. Smith.

1.　　　 The ground __________ (下沉)to the sea.

30.　 t_________ a piece of work done as part of one’s duties, especially hard or unpleasant.

Unit 4