Chọn câu trả lời đúng: ''Have you seen John?'' No. But he ..........be studying in the library

III choose the correct answer
1 ''have you seen John?'' No. But he ..........be studying in the library.
A.will.            B should    C. Needn't.   D.  May
2 Asia I won't be at home tonight, I....... my homework during lunch barak.
 A need to do. B have to do.   C can do. D might do
3 passengers .... smoke until the signs have been switched off.
 A mustn't.       B can 't.   C needn't. D mightn't
4 there are a lot of tickets left, so you ...... pay for the tickets in afvance
A mustn't    B won't.     C. Shouldn't.   D don't have to
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