I didn’t know _______________.
A. when would the train arrive B. who left the message
C. what has been done D. where could I get the book
It is raining heavily outside, ______ we decide to stay at home and watch TV.
A. because B. or C. but D. so
You ______ open the door before the car stops. It’s dangerous.
A. needn’t B. may not C. mustn’t D. don’t have to
Don’t forget ______ thanks when other people help you.
A. to say B. say C. saying D. to saying
Smoking ________ in the forest. It may cause a fire.
A. is not allowed B. is allowed C. doesn’t allow D. allows
I don’t ______ his words, because he often tells lies.
A. speak B. understand C. know D. believe
