用括号中所给词的适当形式填空。

1. You should be much               . It's good for your health. (health)

2. Recently I listened a song               Heart Strings. (call)

3. He told me that he               in that school for 10 years. (teach)

4. I've been (try)               to cheer him up for 20 minutes.

5. The telephone               (invent) before the car.