— Listen! Helen is singing in the classroom.—It _______ be Helen. She has gone to Shanghai.
#74428
A
mustn’t
B
may not
C
can’t
D
should
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My sister met him at the Grand Theater yesterday afternoon, so he _______ your lecture.
#63463
A
couldn’t have attended
B
needn’t have attended
C
mustn’t have attended
D
shouldn’t have attended
---I stayed at a hotel while in New York.---Oh, did you? You ________ with Barbara.
#62807
A
could have stayed
B
could stay
C
would stay
D
must have stayed