按要求改写句子。

1. I'm shorter than he is. (改为一般疑问句)

    _____ _____ shorter than _____ _____?

2. This book is not as interesting as that one. (改为同义句） 

    That book is ____ _____ _____ this one.

3. Tom is thinner than Sam. (同上)

    Sam is _____  as _____ _____ Tom.

4. I'm athletic. He is athletic, too. (合为一句)

    I am _____ _____ _____ he is.

5. He likes swimming. She likes it, too. (同上)

    They _____ _____ doing _____ _____ thing.

外部市场环境是指（）。

A.经济环境

B.治安环境

C.政策环境

D.规划环境

E.自然环境