根据主谓一致原则,主语为复数时,谓语动词也用复数,但当谓语为过去式,谓语就一种形式,不随主语的单复数而改变,如They went to Beijing last year.否定时借助didn,t 加在动词前,不过动词需改为原形,如They didn,t go to Beijing last year..当谓语为系动词be 时,有单复数变化。如He was in the school.They were friends.
一般过去时
主语为复数时,
谓语动词 用过去式;
而否定形式是:
be动词过去式(were) + not;
助动词过去式(did) + not + 行为动词原形;
情态动词过去式(must/should等) + not.
谓语动词用do….have,否定形式用don't,haven't