根据句子意思，用括号内所给词的正确形式填空。

1. David Beckham is a famous football _______ （play）.

2. Mr. Wu teaches _______ （we）English. He is a very good teacher.

3. Linda often helps her friends. She is a _______ （help）girl.

4. Look，the baby has only three _______ （tooth）.How lovely ！

5. Lily and I _______ （be）in the same class. We are classmates.