过去将来时表示从过去的某一时间来看将来要发生的动作或存在的状态。
过去将来时常用于宾语从句和间接引语中。
1)过去将来时的构成（句型如下：）
肯定句：主语+be（was，were）going to+动词原形～.
否定句：主语+be（was，were）not going to+动词原形～.
疑问句：Be（Was，Were）+主语+going to+动词原形～？
肯定句：主语+would（should）+动词原形～.
否定句：主语+would（should）not+动词原形～.
疑问句：Would（Should）+主语+动词原形～？
1.过去将来时的构成
和一般将来时一样，只不过把助动词be变为过去式，把will，shall变为过去式。
I didn't know if he would come.
=I didn't know if he was going to come.
我不知道他是否会来。
She was sixty-six. In three years，she would be sixty-nine.
她66岁了。三年后，她是69岁。
She told us that she would not go with us，if it rained.
她告诉我们，如果下雨，她就不和我们一起去了。
I didn't know how to do it. What would be their ideas？
我不知如何去做，他们会有什么想法呢？
2.过去将来时常可用来表示过去习惯性的动作。
此时，不管什么人称，一律用would。
This door wouldn't open.
这扇门老是打不开。
Whenever he had time，he would do some reading.
他一有时间，总是看书。
I would play with him when was a child.
当我还是孩童时，总是和他一起玩。