Be sure _______ when you enter the cave. Otherwise, you’ll hit your head on the rocks.

"Take this medicine(吃药) and it will make you      better soon," the nurse says to the sick boy.

 —Susan ,you are doing worse. You have to _____more _____ your study than computer games.—Yes. I must control myself.

Do you know the famous man ________ Bill Gates?

--- Where is Mary?--- She ____ to Harbin.