am的过去式是was。was是be动词的第一和第三人称单数（am、is）的过去式，用来表示某人或某物即主语本身，属于某一群体或有某种性质。

say的过去式例句：

1、I was a teacher two years ago.

两年前，我是一名老师。

2、When I was young chocolate was a treat.

我年轻的时候，吃巧克力是一种难得的享受。

3、I was disappointed that John was not there.

我很失望约翰不在那儿。