1. 划线 playing football ,用 what 提问：
What are you doing after school?
你们放学后都干什么?
2. 划线 after school ,用when 提问：
When you will play football?
你们什么时候踢足球?
3. 划线 we are ,用 who 提问：
Who are playing football after school?
谁放学后踢足球?