1、肯定形式：主语+动词过去式+其他。

例句：She often came to help us in those days.

2、否定形式：

（1）was/were+not；

（2）在行为动词前加didn't，同时还原行为动词。例句：I didn't know you like coffee.

3、一般疑问句：

（1）Did+主语+谓语动词原型+其他；例句：Did I do homework?

（2）Was/Were+主语+表语。