考研英语经验谈24-考研英语语法10天速成.docxVIP

考研英语语法10天速成(一)情态动词一.情态动词的现在完成式的用法情态动词现在完成式主要有两个功能：表示已经发生的情况和表示虚拟语气。在这两个方面must/mustnt,; can/cannt; need/neednt; may/maynt; might/mightnt; should/shouldnt; ought等情态动词＋完成式表示的意思是有一定区别的1.表示已经发生的情况。1) must have+过去分词，表示对已发生情况的肯定推测，译为“(昨天)一定……”。如：My pain apparent the moment I walked into the room, for the first man I met asked sympathetically:” Are you feeling all right?”A. must be B. had been C. must have been D. had to be(答案为C.2) cant / couldnt have+过去分词，表示对已发生情况的否定推测，译为“(昨天)一定没……”。如：Mary my letter; otherwise she would have replied before now.A. couldnt have received B. ought to have receivedC. has received D. shouldnt have received(答案为A.3) may / might have +过去分词，表示对已发生的事情做不肯定、可能性很小的推测，或事实上根本没发生，译为“也许……”。如：At Florida Powers Crystal River plant, a potentially serious leakage of radioactive water may have been unknowingly caused by an electrician.2.表示虚拟语气。1) neednt have +过去分词，表示做了不必做的事，相当于”didnt need to do”,译为“其实没必要……”。如：You neednt have come over yourself.As it turned out to be a small house party, we so formally.A. neednt dress up B.did not need have dressed upC. did not need dress up D. neednt 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”，与had better相