4. Don’t______ (踩踏) the grass. We should protect it .

3. Which______ 方向)is the bus coming?

2. Tom was so______ (害怕)that he didn’t know what to do .

1. She didn’t______ (注意到)that she was in trouble.

15. When did you start______ (learn) English.

Section C

14. I am looking forward to______ (see) you again..

13. He spent two and a half______ (day) doing the job.

12. On both______ (side) of the river, there are a lot of small tombs.

11. At the______ (begin) of the meeting, Mr. Wang made a speech.

10. Be careful and______ (确保) that you don’t make mistakes.