在英语语法中，过去将来时是一种用于描述在过去某一时间点来看将来发生的动作或状态的时态。它通常用来表达计划、安排或者预测未来的事件，但从过去的视角来看待这些未来的事情。

构成方式

过去将来时由“助动词will的过去式would”加上动词原形构成。例如：

- 主语 + would + 动词原形

例如：

- She said she would come tomorrow.（她说她明天会来。）

用法详解

1. 表示过去的计划或安排

当我们谈论过去某个时刻已经决定好的事情时，可以用过去将来时。

- Example: He told me he would visit Paris next month.

2. 表示过去的意愿或决心

过去将来时也可以用来表示过去某人打算要做的事情。

- Example: They decided that they would help us finish the project.

3. 表示过去的预测或假设

如果从过去的角度出发对将来的可能性进行推测，也可以使用过去将来时。

- Example: I thought it would rain later in the day.

4. 与条件句搭配

在虚拟语气中的条件句里，过去将来时常用于主句中。

- Example: If I had more time, I would have gone to see him.

练习题及答案

练习题

1. Last year, my teacher promised that we ________ (go) on a field trip.

2. When I called her yesterday, she said she ________ (meet) me at the library.

3. The guidebook suggested that we ________ (start) early in the morning.

4. If you had studied harder, you ________ (pass) the exam easily.

5. By this time tomorrow, I ________ (finish) my homework.

答案

1. would go

2. would meet

3. should start / would start

4. would have passed

5. will have finished

通过以上讲解和练习，我们可以更好地理解和掌握过去将来时的应用场景和结构特点。希望这些内容能帮助大家在学习英语时更加得心应手！