---- Each year __________ fishes are killed by the polluted water and many people are made sick by the polluted air .----So we should do something to stop it .
There is a tall tree _________ my house. I often play games under it.
—What is on the desk? —There ____ a book and two pens on it.
—Jim, which _________do you like best? —I like geography best.
— _______ classes do you have every weekday? —Seven classes.
—______ drive after drinking. It’s too dangerous(危险的). —OK. I won’t.