单选题
As it turned out to be a small party, we ______ so formally. A) needn't dress up B) did not need have dressed up C) did not need dress up D) needn't have dressed up
【正确答案】
D
【答案解析】此题含义为：既然这是个小聚会，那我们就没有必要穿得这么正式了。need可以是情态动词，也可以是实义动词。表示“没有必要做”的含义时，情态动词是needn't do/have done，实义动词是did not need to do。