下列这些词的过去式比较特殊：

am /is、are 、buy 、come、drink、 eat—ate、 feel、fly、do、 get 、go、have、know leave、make、ride、run、say、see、send、sing、sit。

过去式如下：am /is – was;  are – were;  buy—bought;  come—came;drink—drank;  eat—ate;   feel—felt; fly—flew;do—did; get – got; go—went; have—had;know—knew; leave—left; make—made;   ride—rode;run—ran;   say—said;see—saw; send—sent;sing—sang;  sit—sat。

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?