There are a lot _____ students on the playground. A. of B. in C. by
-Robert is _____ to face dangers. Don’t be worried about him. -I think so.
-George is not here. What’s the matter with him? -Her father is ill in hospital. She has to_____ him.
Mike went to the library ____ some books the day before yesterday.
Nancy _____ playing the piano at 7pm. yesterday.
The Great Wall of China is ______wall in the world.