【题目】According to the law, all foreigners have to ______ with the local police within two weeks of arrival.
A.associate
B.dispute
C.negotiate
D.register

A.couldn'tB.mustn't

C.shouldn'tD.needn't

【题目】While intelligent people can often ______ the complex, a fool is more likely to complicate the simple.
A.sacrifice
B.substitute
C.simplify
D.survive

【题目】Not once ________ to Michael that he could one day become a top student in his class.
A.occurred it
B.it did occur
C.it occurred
D.did it occur

【题目】— I don't understand why you didn't go to the lecture yesterday afternoon.
—I'm so sorry. But I _________ my homework.
A.had done
B.was doing
C.would do
D.am doing

【题目】He ________ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.
A.wouldn't
B.shouldn't
C.couldn't
D.mustn't