was加现在分词是什么时态

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?