译为“其实没必要……”。如: You needn’t have come over yourself. As it turned out to be a small house 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 (没有必要穿的那么正式,体现是说话者的建议,实际结果是否真的穿的很正式没有确定,答案为D) 2)should have +过去分词,表示应该做某事但实际上未做,译为“本应该……”should not + have过去分词表示本不应该做某事但实际上做了,译为“本不应该……”。如: I regret having left the work unfinished; I should have planned everything ahead carefully. 我本来应该事先认真地把每件事情规划的很好,但实际上作者还是没有规划好,以至工作没有完成。 3) ought to have +过去分词,表示动作按理该发生了,但实际上未发生,译为“该……”,与should 的完成式含义类似。如: The porter ought to have called the fire-brigade as soon as he saw the fire in the stock, which went up in smoke . 4) could have +过去分词,表示过去本来可以做但却未做,译为“完全可以……”。这点与ought/should/ have +过去分词用法相似。如: What you said is right, but you could have phrased it more tactfully. 5) may/ might have +过去分词,表示过去可以做但实际未做,译为“(那样)也许会……”。如: It might have been better to include more punchy statistics and photos of equipment in the introduction to further assist first-time office automation managers. 二.几个情态动词常考的句型: 1).may/might (just) as well “不妨,最好”