2.Excuse me. I’m sorry I’m late, because the traffic is bad.　

1.Welcome backto school!

11. Good luck(with sb)!

III. 交际用语

10. say goodbye to sb.

9. ask sb. for sth.

8. You’d better do sth.

7. be friendly to sb.

6. Are you going to…?

5. Why not…?

4. start with sth.