用适当的介词填空。
1. Danny isn't ____ school today, and he has been ____ for three weeks.
2. I'm going to play basketball on the playground ____ school.
3. There are plenty      flowers in the garden.
4. What shall we write      our poster?
5. Let's make a poster ____ drinking.
6. Drinking too much is also bad ____ your health.
7. I have an idea ____ your plan.