807.What do you think we can do for our aged parents?
You _______ do anything except to be with them and be yourself.
A.don't have to
B.oughtn't to
C.mustn't
D.can't
808.My MP4 player isn't in my leg.Where _____ I have put it?
A.can
B.must
C.should
D.would
807.答案是A;don't have to 不必。
808.答案是A;can表示推测时，只能用于否定和疑问句：而must必须用于肯定句。
