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。