用适当的代词填空。

1. I'm a nice girl. _____ mother likes me very much.

2. He's Chinese. _____ father is a worker.

3. I don't know _____ telephone number, Tom.

4. —Are you students?

    —Yes, _____ are.

5. Anna is a good student. _____ brother is Peter.

文书工作人员的素质是指什么？