Fill in the suitable words. THANKS
1. We must go to school _________ time.
2. Look!The plane is flying _________the house.
3. There are a lot_________books ______the library.
4. The postman is knocking __________the door.
5. Nurses look _______ the sick.
6. Sweets are bad _________teeth.
7. John paid two hundred dollars ________swimming lessons.
8. I don't like playing tricks ________other people.