一、单选（每题1分，共20分）
1. Here is the book. First __ it and then tell me what you think of it.
A. look into B. look through C. look up D. look after
2. ________stop them polluting the river?
A. Why not B. Why don't
C. Would you mind D. Why don't you to
3. I will have a competition next week and I hope things will ______.
A. work on B. work out C. work for D. work in
