过去将来完成进行时的用法
一、间接引语与过去将来完成进行时
在间接引语中，若主句为过去时态，则用于宾语从句中的间接引语则要把将来完成进行时改为过去将来完成进行时。如：
I know by this time next week you’ll have been working here for 30 years.
→I knew by that time he would have been working there for 30 years.
She will have been teaching in this university for 20 years by this summer.
→She told me she’d have been teaching in that university for 20 years by that summer.
二、过去将来完成进行时与虚拟语气
在特定的语境中，有时过去将来完成进行时可用虚拟语气中。如：
At the time of the accident I was sitting in the back of the car，because Tom’s little boy was sitting beside him in front. If Tom’s boy had not been there I would have been sitting in front. 事故发生的时候，我坐在车子的后座，因为汤姆的小儿子坐在前边他的身旁。要是汤姆的孩子没坐在那里的话，我就会坐在前面了。
三、过去将来完成进行时的情态意义
“would have been+现在分词”结构除用于表示过去将来完成进行时外，运扮有时其中的 would 也可能是情态动词，具有情态意义，比较表示推测或猜想等。如：
“What interesting job have you found?” Helen asked him; he knew she would have been thinking about it.“你找到什么有趣的工作啦?”敏悄饥海伦向他问道。他知道海伦一定会一直想这件事的。
四、过去将来完成进行时补充例句
过去将来完成进行时不是一个常用时态，一般语法书也讲得到很少，所以能找到的权威例句也很少。为满足部分高级读者朋友的需要，特从“英桥返国国家语料库”中查了部分例句，供大家参考：
◇Latterly, they would have been reading Virgin books, watching Virgin videos and Virgin films.
◇New York was swathed in sunlight and the heat would have been stifling had it not been for a gentle easterly breeze blowing in from the Atlantic.
◇Maybe we, it may well be that you were with other people, I wonder what sort of things if you were in a condition of speaking, what sort of things you would have been saying to them.
◇Obviously no expense was being spared to make the night a success, and in different circumstances she would have been looking forward to it, but now, as silence settled over the car, she could feel herself growing tense.
