第1个回答 2012-06-25
Was/ were在一般过去时的句子中做系动词, 与表语连用; 另外就是在过去进行时和一般过去时的被动态用was/ were做助动词。除了上述情况的其他一般过去时直接用动词的一般过去时形式，在进行句型变换时要用到助动词did，如：一般过去时陈述句变成一般疑问句时，用did，同时谓语动词变成原形
第2个回答 2012-06-25
Was/were其实就是is的过去时态，
did是do的过去时态。他们两个的区别同is和do一样。
is用于主系表，做系动词用。do用于一般疑问句或者否定句中做助动词。
说得白了，就是有谓语动词的一般疑问问和否定句用do做助动词，没谓语动词的用is做系动词。
在过去时态中is换成Was/were，do换成did本回答被网友采纳
第3个回答 2013-05-02
在过去时中将is are换成was were.将do does换成did
第4个回答 2012-06-26
was用作系动词：I was at home yesterday. He was a teacher many years ago.
was用作助动词：He was watching at home last night. He was beaten by his father yesterday.
did 用作实意动词：He did his homework yesterday evening. She did some washing instead of her mother yesterday.
did 用作助动词：He didn't do his homework yesterday evening. Did she do any washing instead of her mother yesterday?
was用于主系表结构的句式中，也可作为助动词用于过去进行时或被动语态中。
did作实意动词用，是“做，干”之意，作助动词可以帮助行为动词构成否定句或一般疑问句。