1.概念：过去某个时间里发生的动作或状态；过去习惯性、经常性的动作、行为；

2.时间状语：ago,yesterday,the day before yesterday,last week,last(year,night,month…),in 1989,just now,at the age of 5,one day,long ago,once upon a time,etc.

3.基本结构：be动词；行为动词的过去式

4.否定形式：was/were+not;在行为动词前加didn't，同时还原行为动词。

5.一般疑问句：was或were放于句首；用助动词do的过去式did提问，同时还原行为动词。

6.例句：She often came to help us in those days.