was是be动词的过去式。was后面动词可以是现在分词，构成过去进行时态；可以是过去分词，构成被动语态；was作系动词时，后边接现在分词、动名词短语作表语，还可以接过去分词作表语。

be动词例句

The man is a science teacher.

这个男子是一位科学教师。

Mary's new dresses are colourful.

玛丽的新衣服色彩鲜艳。

I have been there before.

我以前去过那里。

My mother is in the kitchen now.

我妈妈现在在厨房里。

这四个都是陈述句，可以变成疑问句，方法简单，把主语和“be”或助动词对换位置即可：

Is the man a science teacher?

Are Mary's new dresses colourful?

Have I been there before?

Is mother in the kitchen now?