is的过去式是什么

is的过去式是was，其否定形式为was not或wasn’t，其过去分词是been，例如“The system was state of the art”意思为这一系统是当时最先进的。be动词is、am的过去书都为was，例如“I was ten years old in 2008”意思为2008那年我10岁。

相关例句：1、It was a time of peak demand for the product.

那是对该产品需求最旺的时期。

2、She was still half asleep when she arrived at work.

她到了上班地点时仍然睡眼惺忪。

3、It was on TV not long ago.

电视不久以前播出了这个节目。

4、There was an almost complete lack of awareness of the issues involved.

对有关问题几乎是一无所知。

5、I was still awake when he came to bed.

他就寝时我还没有入睡。