21. sometimes , sometime , some time

(1)They visited our school _____ last year .

(2)It took me _____ to do the work .

(3)_____ I watch TV in the evening .

19. either , any

(1)You may take 　　　　of the two books .

(2)Here are three balls . You can take 　　　　of them .

17. each , every

(1)　　　 　student must work hard at his lessons .

(2)　　　 　has his own name .

16. what , how

(1)　　　 　a nice watch it is !

(2)　　　 　hard she works !

(3)　　　 　she missed her daughter !

15. everyone , every one

(1)　　　 　of the books is very useful .

(2)　　　 　likes sports .

14. take , bring

(1)May I 　　　　this book home ?

(2)Remember to 　　　　the box here tomorrow .

13. look for , find

(1)I 　　　　him at home at last .

(2)I’m 　　　　him now . Do you see him ?

12. borrow , lend

(1)I 　　　　a book from the library yesterday .

(2)You mustn’t 　　　　it to others .

11. go to bed , go to sleep

(1)It’s time to 　　　　.

(2)He was tired . He 　　　　as soon as he sat down .

10. look at , see

(1)I didn’t 　　　　any boats on the river .

(2)What are they 　　　　?