用所给词的适当形式填空。

1.  He enjoys____   (tell) jokes.

2. Most of the____   (kid) are very lovely.

3.  She likes to have friends who are____   (difference) from her.

4.  Please tell me its____   (important).

5.  Tom is much____   (quiet)  than his friends.

我国发现的抗疟新药青蒿素，作为开发抗疟药的先导物发现的途径是

A．从随机筛选中发现的先导物
B．从天然资源中发现的先导物
C．从生命基础过程研究中发现的先导物
D．经组合化学方法发现的先导物
E．从活性代谢物中发现的先导物