二、根据所提供的情景，用适当的情态动词完成句子。
1.You ________ (drive) if you are drunk, first because it's dangerous and second because it's against the law.
答案 can't/mustn't drive
2.As it turned out to be a small party, we ________ (not dress) up so formally.
答案 needn't have dressed
3.How ________ I help them to understand when they won't listen to me？
答案 can
4.Don't you think it essential that every person of Brazil ________ spare no effort to make contributions to the 2014 FIFA World Cup？
答案 should
5.She ________ comb her hair at the table, even though she knows I don't like it.
答案 will
6.—She looks very happy. She ________ (pass) the exam.
—I guess so. It's not difficult after all.
答案 must have passed
