一般过去式的特殊用法

肯定句中的过去时态，be动词或者动词要用过去式，比如was，were，实意动词要用过去时态，do当实意动词讲时，要用did
例如：He was a student many years ago.很多年前他是个学生
I went to cinema last week.我上周去了电影院（went是go的过去时）
I did my homework last week.
我上周做了家庭作业（这里did是do当实意动词的过去式）

否定句中的过去时态，be动词要用过去式+not，或者助动词did+not
I were 15 years old last year.我去年15岁
I didn't go to school yesterday.我昨天没去学校
I didn't do my homework yesterday.我昨天没做作业（这里didn't是助动词，do是实意动词）

疑问句中，提问时be动词要用过去式，或者用主动词Did
Were you 15 years old last year?你去年是15岁么？
Did you have a good meal?（你吃得好么）did后的动词统统要恢复原形，不管是现在进行时还是什么什么时，总之无论是什么事态都要恢复原形。否定句时在did后直接加n't即可。