语法在英语考试中有着举足轻重的地位,不管是完型、阅读、翻译、还是作文,都离不开语法。那么考研英语中的语法小伙伴们都掌握了吗?今天小编就给大家整理了入门语法篇,一起来看看吧。

现在完成时

现在完成时既涉及过去,又联系现在,主要有两种用法。

一、表示过去发生或已经完成的某一动作对现在造成的影响或结果.常与just(刚刚),already(已经),never(从来没有),ever(曾经),before(以前),yet(仍然),once(一次),twice(两次),many times(很多次),how many times(多少次),so far(迄今为止),during the past(last)three years(最近三年来)等连用.

※副词的位置:

  (1)just常用于肯定句中,放在have / has后,He has just come .

  (2)never表示否定, 放在have / has后, He has never visited the Great Wall.

  (3)ever用于疑问句中,句型为: Have / Has+主语+ever +过去分词?“…曾经……过吗?”用于询问某人过去的经历.Have you ever been to the farm?

  (4)before用于句末,The woman has never heard of that before.

  (5)yet 用于句末或not 之后.Has the train arrived yet? No, not yet.

  (6)already用于肯定句, have / has 之后或句末.We have already finished it.

  (7)so far用于句首或句末. So far, we have visited the moon.

 

二、表示过去已经开始,一直延续到现在的动作或状态.时间状语有:

  (1)for+表示一段时间的词语I have taught English for 19 years.

  (2)since+表示过去时间点的词语He has been at this school since 1986.

  (3)since+表示过去的时间状语从句I have lived here since I was born.

  (4)since+一段时间+ago. I have known him since 20 years ago.

 


过去完成时

过去完成,顾名思义,就是表示在过去某一时间之前已经发生或完成的动作,也就是我们所说的“过去的过去”。因此,它有“已完成”用法和“未完成”用法。结构为:had+-ed分词。

一、“已完成”,表示一个动作或状态在过去某时之前已经完成或结束

  I had finished my homework when my friends came.我朋友来的时候,我就已经完成家庭作业了。

  My father had left for Beijing before I came home. 在我到家前,爸爸已经离开去北京了。


二、“未完成”,表示一个动作或状态在过去某时之前已经开始,一直延续到这一过去时间,而且到那时还未结束,仍有继续下去的可能性。

  Jack said that he had made much progress in English since he came here. 杰克说自从他到这儿以后,英语已经取得了很大进步。

  By six o’clock these workers had worked twelve hours. 到六点钟时,这些工人已经工作十二小时了。


三、连词引导过去完成体用法:有些连词引导的过去完成时可互换。

  When I reached the station, the train had already left.

  =I reached the station after the train had left.

  =I didn’t reach the station until the train had left.

  =The train had left before I reached the station.

  在我到车站时,火车已经走了。


四、过去完成体的虚拟用法,表示与过去事态相反的主观设想。

  (1)用于if, if only, as if引导的分句:

  If you had worked hard, you would have passed the exam. 如果你努力学习的话,你就已经通过考试了。

  If I were you, I would not do it. 我要是你,就不做这事。

  If only I had finished it before. 要是我之前完成了这件事就好了。

  I felt as if I had been a bird in the sky.我感觉自己好似天空一只小鸟。

  (2)用于I wish, I would rather引导的that从句:

  I wished that I had knew the answer to the question before he asked me. 我希望在他问我以前,我知道问题的答案。

  I would rather you had told me the truth. 我宁愿你跟我说实话。

  (3)用于expect, think, intend, mean, want, suppose等表示过去未曾实现的希望、打算或意图。

  I had intended to buy a present for you, but I forgot that. 我本打算给你买礼物的,但我忘了。

  I had hoped that we could pass the exam, but we failed in the end. 我本希望我们都能通过考试,但最终我们失败了。

因此,由上可知,比起现在完成体,过去完成体用法复杂,且具体“虚拟”的特殊用法,需要我们在平时使用中加以注意。



现在完成进行时

我们在使用现在完成时之前,还应该了解和它相似的现在完成进行时。

现在完成进行时态的动作表示从过去某一时刻开始一直延续到至今,它强调动作的整个过程。这个动作也许刚刚结束,也许仍在进行。

  现在完成进行时态的用法:

  例句:

  (1) What have you been doing all this time? 这半天你干什么来着?

  (2) I have been waiting for my girl friend for half an hour, but she has not shown up yet. 我一直在等我女朋友,已等了半小时,但她仍没露面。

  (3) He is ill. He’s been lying in bed for three weeks. 他病了。已卧床3个星期。

  (4) I have been watching TV the whole evening. 我整个晚上一直在看电视。

  现在完成进行时态并不难掌握,它的特点是强调动作的过程。



现在完成时与现在完成进行时的区别

在实际使用过程中,有时候很容易把现在完成时和现在完成进行时混淆,那么二者有哪些区别呢?

  (1)现在完成时可以表示一个已经完成的动作,而现在完成进行时则表示一个正在进行的动作:

  I have read the book. 我读过这本书。

  I have been reading the book. 我一直在读这本书。

【注】有少数动词(如work, study, live, teach, stay等)在表示持续一时间时用这两种时态含义差不多(只是用现在完成进行进更强调动作的持续性):

  How long have you worked [been working] here? 你在这儿工作多久了?

  I’ve lived [been living] here since 1988. 自1988年以来我就一直住在这儿。

  (2)现在完成时通常只陈述事实,而现在完成进行时还可表示一种感****彩:

  I have waited for two hours. 我等了两小时。(陈述事实)

  I have been waiting for two hours. 我等了两个小时。(等得好辛苦)

  (3)现在完成进行时通常用来谈论较短暂的动作或情况,若要谈论时间延续较长的动作或情况或永久性情况,则通常用现在完成时:

  He has lived in Paris. 他(一直)住在巴黎。

  He has been living in Paris. 他(目前)住在巴黎。(表暂时性)

  (4)不用于进行时态的动词通常也不用于现在完成进行时,但它们可以用于现在完成时:

  I’ve only known her for two day. 我认识她刚刚两天。

  They’ve been married for twenty years. 他们结婚已二十年了。

  The war has lasted for a long time. 这场战争持续了很长时间。

  (5)现在完成进行时不用于被动语态,若要用可用现在完成时的被动语态代替:

  The house has been painted for a month. 这房子已漆了一个月。

  The problem has been studied for five days. 这个问题已研究了五天。

 

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