Unit3 Places of interest-grammar 学案 过去完成时有两种基本用法:“段”的用法和“点”的用法
“段”的用法——表示一个动作或状态在过去某一时刻之前开始,一直延续到这一过去时刻,甚至还可能继续延续下去(To express duration up to or into a certain time in the past)
这种用法通常见于延续动词作谓语,且常和表示时间段的状语连用
例如: She looked rather pale
She had been ill for some time
When we got to the cinema, the film had been on for half an hour
He said he had made great progress since he came here
By the time I left the school, I had taught that class for two years
Until then I had known nothing about this
They had walked only a few steps when a second group of tanks drew up on the side road
“点”的用法——表示一个动作或状态在过去某一时刻之前(已经)发生或完成(即过去之过去)
有时仅表示两个(或两个以上)动作或状态在时间上的先后关系,有时也包含前者与后者的联系或对后者的影响的意义
这种用法多见于非延续动词作谓语,且常和表示时间点的状语连用
例如: When we got to the cinema, the film had already begun
I was not sure wh