It is hard to say what kind of person he is.Sometimes he is very friendly; at other times he ___ be very cold.
Hurry up, or you ______ catch the train.
You can improve your English ______ practicing more.
—What’s wrong with you, Eric? You look tired. —I ______ to prepare for the final exam last night.
Tony is not as clever as Lucy, but he works ______ than her.
—Why are you excited today? —We have been told ______ a picnic this weekend.