5.1 完成时态的构成

现在完成时：have worked
过去完成时：had worked
将来完成时：will have worked

5.2 完成时态的意义

“回顾retrospect”，就必然要涉及两个时间点，即从一个时间点回顾到另外一个时间点，因此完成时态必定涉及前后两个时间。

完成时态表示的就是一个横跨前后两个时间点的事件，主要通过下列三种方式：
1. 一个事件从一个时间点“延续（continue）”到另外一个时间点；
2. 一个事件从一个时间点“重复（repeat）”到另外一个时间点；
3. 一个事件在前一个时间点已经结束，但它的影响“延续”到另外一个时间点。

5.4 延续事件

5.4.1 过去的事件“延续”到现在

We have been in love for eight years and we are getting married next month。

5.4.2 “延续事件”与时间状语的关系

一、谓语要表示“延续”
谓语必须是延续动词，如前面例句中的learn/live，或者是能够表示延续状态的词，如be动词。
I have fallen in love for eight years. （×）
I have been in love for eight years （√）
因为这里的fall是短暂动词，无法与延续性的时间状语（for eight years）连用。而不是短暂动词不能用于现在完成时态。（I have fallen in love 正确）

二、要与“延续性时间状语”连用
表示延续思维的完成时态除了要有延续性的谓语之外，还必须有延续性的时间状语。具体来说，这种表示延续性动作或状态的完成时态一般必须接一个表示“一段时间”的延续性时间状语，以说明某个动作或状态持续到现在有多久了。

• since+时间点或从句

Since time began, man has lived in fear of fire.

• for+时间段

Great changes have taken place in Beijing for the past few years.

• “到目前为止”, “迄今为止”：until now, up until now, up to now, up till now和so far等

We have up until now failed to take any action to decide on a common language that would further communication between nations.

• “在最近几个/年/月以来”：in the past few years, over the past few years, during thelast three months, for the last few centuries, through centuries和throughouthistory等

Throughout history man has had to accept the fact that all living things must die, for the very nature of life includes death.

三、没有延续性的时间状语，则表示一个“完成了（complete）”的动作
若没有延续性的时间状语，可以用完成时态，但表示的是一个在过去已经完成的动作，而没有延续到现在。

• John has lived in Paris for ten years.
• John has lived in Paris. That was ten years ago. He is now living in Beijing.

  5.5 重复事件

  5.5.1 过去的事件“重复”到现在

  “For us this has been the most perfect way to remember her, and this is how she would want to be remembered.”

  5.5.2 “重复事件”与时间状语的关系