What are you going to do this afternoon?
I'm going to play baseball.
- 你下午要做什么?
- 我要打棒球.
或：
Are you going to play baseball this afternoon?
Yes,I am.
- 你下午要打棒球吗?
- 是的,我会打的.
或：
When are you going to play baseball?
This afternoon.
- 你要什么时候打棒球?
- 今天下午.