1.I spent two hours in ____________ (do) my homework.

2.We look forward to _____________(see) our parents.

3.They are used to ________________(live) in Shanghai.

4.The knife is used for _____________(cut) things.

5.He kept on ___________(write) the letter last night.

6.Li Ping and Wang Lin went on ________(work) after they had a rest.

7.Lucy and Lily went on _________(do) their homework after they had finished the work.

8.The strong wind stopped them from _______ (go) out.

9.The river prevents us from ________ (go) to school.

10.I kept the children from _________(fight) each other.

11.He is fond of __________ (play) sports.

12.We succeed in _________(finish) the novel.

13.The scientist has made a great contribution to ____________ (develop) our science and technology.

14.Thanks for ________ (help) me .

15. I prefer ________(play) basketball to ________(stay) at home.

16.The teacher devotes him to __________(teach) his students.

17. I finished _________ (write) the letter just now.

18.The boy enjoys _________(watch) cartoons.

19. I mind __________ (smoke) here.

20.He minds not ____________(open) the window.