句型转换。

1. When he was 8,he began to learn to skate. (改为同义句)

                                            _________ _________eight , he                 to learn to skate.

2. It takes about15 minutes to walk home. (就画线部分提问)

             _______    ________It            to  walk  home?

3. I think Jim will come back. (改为反意疑问句)

I think Jim will come back,               _________?

4. I'm planning to visit my teacher this Sunday. (就画线部分提问)

                        _______   _________  _______Planning               this Sunday?

5. "Are you going to visit Zigong next week?"Father asked me.(改为间接引语)

Father               me                                 ________going to visit Zigong the next week

变性蛋白质的主要特点是（）

A.分子量降低

B.溶解性增加

C.共价键被破坏

D.生物学活性丧失

E.不易被蛋白质水解