文档介绍：考研英语语法10天速成
情态动词
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/mustn’t,;can/cann’t;need/needn’t;may/mayn’t;might/mightn’t;should/shouldn’t;ought等情态动词+完成式表示的意思是有一定区别的
。
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)can’t / couldn’t 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] couldn’t have received [B] ought to have received
[C] has received [D] shouldn’t 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 Power’s Crystal River plant, a potentially serious leakage of radioactive water may have been unknowingly caused by an electrician.
。
1) needn’t have + 过去分词,表示做了不必做的事,相当于”didn’t need to do”,译为“其实没必要……”。如:
You needn’t e 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