主语+was/were+现在分词…

肯定句

Millie was drawing a picture when Mr Green

come in.

当格林先生进来时，米莉正在画画。

When Jim's mom came in, he was doing his

homework.

吉姆的妈妈进来时，他正在做作业。

Sorry. I was swimming with my friends at

that time .

对不起，我那时正在和朋友一起游泳。

I saw him in the library yesterday. He was

reading a book at that moment.

昨天我在图书馆看见他了。那时他正在读一本书