11. Have you ever been a babysitter?

10. Thanks for helping me.

9. My bike is broken. May I use yours?

8. It's very warm today, isn't it?

7. Let's play football.

6. It's time to stop swinging, John.

II.

5. This is the first time Mary has been a babysitter.

4. What a sunny day!　

3. Don't fall off. Hold on to my hand.

2. It's dangerous in the tree. Please come down.