句法结构
肯定形式：主语+动词过去式+其他
例句：She often came to help us in those days.
否定形式：主语+didn't +谓语动词原型+其他
①was/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.
一般疑问句：①Did+主语+谓语动词原型+其他？ ②Was/Were+主语+表语?
例句：Did I do homework?
一般过去时的特殊疑问句：疑问词+ did+主语+动词原形+其他？
疑问词+was/were+主语+表语？
被动语态：主语 + was / were + 动词的过去分词