3. A. stayed    B. came C. dropped     D. fell

2. A. wonder B. understand        C. reply D. believe

1. A. tell        B. answer      C. give   D. realize

25、It won't hurt to take an umbrella with you.带把伞去总没有坏处。

24、help oneself to 擅自带走；自用

23、explain sth. to sb. 向某人解释某事

22、introduce sb. to sth. 把某事介绍给某人

21、in this respect（way）

20、share many experience＝have many experience in common