- 描述以过去时来写的故事背景，例如："The sun was shining and the birds were singing as the elephant came out of the jungle. The other animals were relaxing in the shade of the trees, but the elephant moved very quickly. She was looking for her baby, and she didn't notice the hunter who was watching her through his binoculars. When the shot rang out, she was running towards the river..."
- 描述未完成的动作，这个动作被另一个动作或事件给打断了。例如："I was having a beautiful dream when the alarm clock rang."
- 表达改变心意。例如："I was going to spend the day at the beach but I've decided to get my homework done instead."
- 与「wonder」连用，让要求的语气变得很客气。例如："I was wondering if you could baby-sit for me tonight."
- They were waiting for the bus when the accident happened.
- Caroline was skiing when she broke her leg.
- When we arrived he was having a bath.
- When the fire started I was watching television.
任何动词的过去进行时都是以两个要素构成：Be 动词的过去时 (was/were)，以及主要动词原型 +ing。
|主词||was/were||动词原型 + ing|
过去进行时，以 to play 为例
|I was playing||I was not playing||Was I playing?|
|You were playing||You were not playing||Were you playing?|
|He was playing||He wasn't playing||Was he playing?|
|We were playing||We weren't playing||Were we playing?|
|They were playing||They weren't playing||Were they playing?|