My teacher said to me with a smile, “Well, you ________ to worry about your lessons.”

I once lived in a house _______ roof has fallen in.[ ]

Tom is _______ honest boy. His hobby is playing _______ violin.

Can you tell me how to learn Chinese well? —Sure. The best way _____ Chinese is often using it more.

If there ______no buying and selling of animals, there ______no killing in nature.