在谈论过去的地点、事件、事物和人时，be动词就要使用过去式：was或者were。

was是is和am的过去式，were是are过去式，使用的时候要注意主谓一致。

例如：

It was a sunny day yesterday. 昨天天气晴朗。

They were too busy to go shopping. 他们太忙，以至于没空去购物。

was和were的否定可以直接在后面加上not，变成wasn't (was not)或者weren't (were not).

比如：

I wasn't in town last week. 上周我不在城里。

They weren't ready to get married then. 他们那时没准备好结婚。

例句:

He was not in London at that time.

他那时不在伦敦。

We were late for the exam last week.

我们上周考试迟到了。

It was a great time seeing him again.

再次见到他很开心。