句法｜3.3 完成时态

完成时态概述

形式：have/has done；had done；will have done
意义：完成时态表示的是在（现在、过去或将来的）某一特定时刻之前开始发生并持续到这一特定时刻或对这一特定时刻有影响的一个活动。

现在完成时

形式： have/has done
概念： 现在完成时表示在现在之前（即过去）开始并持续到现在或对现在有影响的动作。
例句： I have learned 2000 words so far.
解释： 动作learned在“现在”之前开始发生并持续到现在。

过去完成时

形式： had done
概念： 过去完成时表示在过去的过去开始并持续到过去某一时间或对过去有影响的动作。
例句： I have learned 2000 words by the end of last year.
解释： 动作learned在the end of last year之前开始发生并持续到the end of last year。

将来完成时

概念：将来完成时表示在将来之前（可能是过去、现在或将来）开始并持续到将来或对将来有影响的动作。
例句：I will have learned 3000 words by the end of next year.
解释：动作learned在the end of next year之前开始发生并持续到the end of next year。

现在完成时表示一个发生在过去的并且对现在仍有影响的动作，或表示开始在过去，并且一直延续到现在，甚至还可能延续下去的动作。

1. 现在完成时的结构为“组动词have/has+动词的过去分词”。
   • I have finished my homework.
2. 表示发生在过去对现在仍有影响的动作时，常用的时间状语有“already，yet，just，twice，never，before”等
   • We have never seen such fine pictures before.
   • Tom has already gone to America.
   • Have you compketed those tasks yet?
3. 表示在过去就开始，并一直延续到现在，也许延续下去的动作，常用的时间状语有“for+时间段，since+时间点”或者since引导的时间状语从句。
   • I have been away from my hometown for 12 years.
   • Uncle Li has worked in this company since 2000.
   • Tom have learnt Chinese since he was 8.
4. 英语表达have got往往就是表示have（有）的意思。
   • They have got hundreds of books in their house.
5. have gone to和have been to的区别。
   • have gone to:已经去某地，表示此人已经不在这里.
     • Lily has gone to Tianjin.
   • have been to:已经去过某地，表示人去了，已经回到这里了.
     • Lily has been to Tianjin.
   • —Do you know something about Shanghai?
   • —Yes, I have been to Shanghai three times.

3.3.1 过去将来时的语法表达

过去将来时：表示从过去的某个时间看来将要发生的动作或存在的状态。

1. 过去将来时由“should或would+动词原形”构成。第一人称用should，其他人称用would。在美语中，过去将来时的助动词一律用“would+动词原形”。
   • They were sure that they would succeed soon.
   • I thought I would reach there on time.
2. 在时间状语从句和条件状语从句中不可以使用过去将来时，而应该使用一般过去时。
   • Tom promised that he would pay me a lot if I help him with Chinese.
   • Every time when she was free, she would go to pay a visit to her grandmother’s.
3. 表示纯粹的将来时用would或should，表示打算或主观认为的事情用was/were going to+do。
   • She told me she would be 17 next month.
   • Tom told us that he was going to make a speech in front of all the students.

3.3.2 过去完成时的语法表达

1. 过去完成时表示过去某一时间或某一动作发生之前已经完成的动作。简言之，过去完成时可以简单理解为“过去的过去”所发生的动作。
   1. 过去完成时的结构为“had+动词的过去分词”
      • He told me that he had won the speech competition.
   2. 过去完成时的时间状语通常是“by+过去的时间点”或者when，before，after引导的时间状语从句。
      • I had drunk 5 tins of orange by yesterday.
      • They had already finished the tests when their teacher came.
      • The man had left before Tom realized he was a cheat.
      • After I had took off my hat, I walked into my uncle’s.
   3. 过去完成时也常用在宾语从句中。
      • He said that he had never seen a tiger before.

完成时难点解析

瞬间性动作和延续性动词
判断下面两句话是否正确：

• I have arrived in Beijing for 10 days.【错】
• I have been in Beijing for 10 days.【对】

在完成时中，一个瞬间性动词（一次性动作）不能与表示一段时间的状语连用，此时须将该瞬间动词改为延续性或者状态类动词。

现在完成进行时的表达

现在完成进行时：主要是指一个从过去就开始一直延续到现在并有可能继续下去的动作，它具有现在完成时和现在进行时的双重特征。结构是“have/has+been+动词的现在分词”。

• How long have you been waiting for me here?
• I have been swimming in the cold water for about five hours.
  注意：表示短暂动作的动词（如：finish, marry, get up, come, go等）不能用这种时态。