过去时是指已经过去的事情 一般会出现这些词语:last……yesterday……ago等 如:I played the basketball last week 结构是主语+动词过去时 过去进行时指的是过去(确切时间段)发生的事情 如:when I was going to my brother's home,I saw my teacher 结构是主语+was/were+动词ing形式 值得一提的是,如果是瞬间动词.如:arrive、see等一瞬间就能完成的就必须用过去时了,例句:I finished my homework an hour ago.