用所给词的适当形式填空。
1. Please ___ (not) run in the classroom.
2. I'm ___ (eat) some bananas.
3. She often goes ___ (shop) with her mother on Sunday.
4. Please ___ (not play) in the street.
5. The boy is too young ___ (go) to school.
6. Which is ___ (fast), a train or a plane.
7. This shirt is ___ (cheap) than your shirt.