14.　　　　 By the time I got home, my parents ____________ (have) supper.

13.　　　　 He said he____________ (be) to the Great Wall four times.

12.　　　　 I think the computer ____________ (invent) before the TV.

11.　　　　 He ___________ (live) in Beijing since he was eight years old.

10.　　　　 If it __________ (be) fine, we’ll go fishing tomorrow.

9.It takes me half an hour __________ (walk) to work every day.

8.It’s raining now. We have to put off ____________ (have ) a picnic.

7.You’re only twelve years old. Don’t get your ears _____________ (pierce).

6.When they are together, they talk instead of __________ (do) homework.

5.Students should be ___________ (allow) to study with friends.