The citycleaners____ repeat their work many times a day during the dust-storm season.

The citycleaners____ repeat their work many times a day during the dust-storm season.
A.may B.can C.might D.have to
Must I go with them tomorrow?No,you____.
A.mustn't B.shouldn't C.needn't D.can't
He ___ be in his office,for I saw him in the street just now.
A.can't B.shouldn't C.mustn't Dneedn't
Excuse me,_____ you show me the way to the shation?
A.must B.shall C.may D.could
After a long walk,the old man ____ be tired.
A.can B.must C.can D.should
第一题中city和cleaners中间有空格