As it turned out to be a small party in the house, 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
A. A．needn't B.did C.did D.needn't
【参考答案】
D 本题考查情态动词，根据题中的原因状语从句意思(原来只是一个家庭聚会)的提示，可知主句应该是'我们本不必穿得如......