have用于第一第二人称（i ,you),has用语第三人称he/she
was/were是is/are的过去时.放主语后面 做谓语
should/would 后跟动词原形 should是应该是意思.语法should have done(done意思是动词过去分词）意思是本应该做什么,实际是却没做,WOULD ,一般用法,WOULD LIKE TO do sth,意思是更愿意做某事
did是DO的过去时,does是DO的复数形式,
do和does是一般现在时的助动词, did是一般过去时的助动词,does
用于第三人称,而do是第一人称,用于疑问句
eg,How do you know the answer?
How does she know the answer?
Where did he go yesterday?
should do 常用在一些建议类词后引导的句子
i suggest that you should give my 悬赏分：20
而 would do 用在 表示与现在情况不相符情况下的一种假设用句