题目内容：

根据下列各句意思及所给单词的首字母或汉语提示，写出该单词的正确形式。

1.I hope this summer holiday will be _____________(有益的) to your study.

2.He was the only _____________( 目击者) of the accident, who would give important information.

3.Statistics _____________(表明) that the world population has doubled.

4.Tom was ___________(推选) chairman, for he is hardworking and responsible.

5.Can you _____________(推荐) a good dictionary to me ?

6.I wonder if you’ll c_________________ them all on their success.

7.She had a strong d_______ to go abroad for further study.

8.He was a_________ of wind in his face.

9.All the students p_______________ in cleaning the street.

10.He o________ his success to the good education he received.