You will not win the first prize ________ you work harder.
A. if B. unless C. or
Our playground is not so tidy and beautiful as before. Students must _____ dirty things on it.
A. be stopped to throw
B. be stopped from throwing
C. stop to throw
—Must I give up drinking coffee, doctor?
—No, you _________. Drinking coffee is good for your health.
A. can’t B. mustn’t C. needn’t
— Could you tell me ___________? I must prepare for it.
— Well, it will start at 9:00 tomorrow morning. There is enough time for you.
A. why will the speech start
B. when the speech will start
C. where the speech will start
It is _______ for them _______ the problem.
A. difficult; to deal with
B. difficulty; dealing with
C. difficult; dealing with