用所给词的适当形式填空。

1. We should learn from _____(hero).

2. I would like _____ (help) her teach our English class.

3. She asked me _____ (make) an example of a crossword puzzle.

4. He _____ never _____ (tell) me the story before.

5. The vegetables _____ (eat) up by the sheep just now.

进化观点分析，动物的保护色是（　　）

A．环境变化的结果

B．人工选择的结果

C．自然选择的结果

D．动物聪明的表现