按括号中的要求完成改写后的句子，每个空格填一个单词。

1. My uncle is walking the dog in the park. （改为否定句）

My uncle ______________ _____________ the dog in the park.

2. I have already been to the World Expo with my parents.（改为一般疑问句）

______________ you been to the World Expo with your parents ______________?

3. The teacher asked me, “ Will you be a volunteer in Yushu? ” （改写句子，句意不变）

The teacher asked me if ___________ ____________ be a volunteer in Yushu.

4. People will care for the environment if they realize the importance of protecting it.

（改写句子，句意不变）

The environment will ______ ______ for if people realize ______ _____ it is to protect it.