⒈ 表示过去某个时间发生的动作或存在的状态
eg : ①He was at home yesterday .
②I got up at six thirty yesterday morning .
⒉ 表示过去经常或反复发生的动作
eg :①My father often went to work by bus last year .
②When I was a child, I often listened to music .
⒊ 过去接连发生的动作
eg : He got up, washed and left for work .
