I always forget some news . I am very upset. and don' t know _______ . A. how to do. B. when to do. C. what to do .
I like playing ____ football, but I don’t like playing____ piano.
I think teenagers should be allowed to go to meet internet friends alone. —_________. It’s too dangerous.
—Could you tell me _______at the meeting? —Sorry, I don’t know. I didn’t attend it.
Now air in our town is ____ than it used to be. Something must be done to it.
—Do you know the girl _____is standing under the tree? —She is my little sister.