单选题 --I wonder why Mary didn't come to the examination yesterday.
--She ______ since she had already passed it.
A. didn't need to B. needn't take it
C. needn't to D. needn't have taken it

【正确答案】 A

【答案解析】[解析] didn’t need to(do sth．)不需要(做)，指过去没有做某事，也没有必要做。needn’t have done sth．没必要做，表示已经做了，但没有必要做。