资源看点：分课基础知识练习，同步实用。

Lesson 21

I. 根据句子意思用适当的介词填空。

1. ________ my surprise, he came too early this time.

2. What do you usually do ________ Sunday morning?

3. I think we are _________ great danger now.

4. We should make friends _________ animals. Do you think so?

5. There are all kinds ________ animals in this zoo.

II. 用括号中所给词语的适当形式填空。

1. They felt ________ at our coming. (surprise)

2. It’s too __________ to play with fire. (danger)