He doesn’t ________ anything we may say to help him study math.
________ Mayan(玛雅)Calendar marks the end of the earth around December 22, 2012, which has caused ________ great panic among people.
— Shall we go out for a walk? — Oh, ________.
— My son spoiled your carpet. Let me buy you a new one. — ________.
Natural disasters occur at ________ times, so it is always difficult to warn people in advance.
________ when your ticket has been checked will you be allowed to take the plane.