According to the school rules, no student _______ go out of school without the permission of the teachers.

Mr. Bush is on time for everything. How ____ it be that he was late for the important meeting?

—Mr. Wang __________ be in the office. The light is still on.—No, he __________ be. Because he phoned me from the farm just now.

 He had no choice but to go on because it is their agreement that no one ______ quit the plan half way.

--- Mary’s got crazy and has been sent to the mental hospital. Did you tell her boss about that?--- Yes, but I _____ her husband first.