过去将来时态的基本构成：would ＋ v．(原形)，表示从过去某时开始将要发生的动作或存在的状态，常用于宾语从句中；也常可表示过去习惯性的动作(不管什么人称，都用would)。
[观察思考]
①They set off at 9 a．m.and would reach the airport an hour later.
②I was going to leave，but then it began to rain.
③He said he was to finish the work in a week.
④He was about to get on the bus when someone called him.
⑤Tom said that he was flying to Germany at five this afternoon.
[归纳用法]
1．过去将来时态的基本表达形式：would＋do
He hoped that they would meet again some day.
他希望将来有一天他们能再见面。
2．表示过去将来时的其他几种表达形式：
①was/were going to do，表示准备、计划做。
She said she was going to buy a new bike.
她说她打算买一辆新自行车。
②was/were about to do，表示即将发生的动作，不和表示时间段的状语连用。
The bus was about to start.
公共汽车马上就要开了。
③was/were to do，表示过去曾计划或安排要做。
The press conference was to be held the next week.
记者招待会将于下周举行。
④was/were doing仅限于某些表示位移的动词，如：come，go，arrive，leave等。表示按计划或安排将要发生的事。
I didn't know when they were coming again.
我不知道他们什么时候再来。
⑤用某些动词的一般过去式形式表示按计划或时刻表要发生的事。
They told me school began on September 1st.
他们告诉我9月1号开学。
3．was/were to do结构， was/were about to do结构以及was/were going to do结构的区别：
①was/were to do侧重受别人指示或安排要做；
②was/were about to do表示说话的瞬间就会发生的动作，一般不与表示将来的时间状语连用；
③was/were going to do侧重说话人的意图或打算。
Mr.Smith said he was to take up the position.
史密斯先生说他要接任这个职务。
I felt something terrible was about to happen.
我觉得有可怕的事要发生了。
He promised me he was going to write the article well.他答应我会把文章写好。
