过去完成进行

过去完成进行时用来描述一项活动在其他事情发生之前已经进行了多长时间。

这种时态常与下列时间短语连用:

... for X hours, days, months, 等等

... since Monday, Tuesday, 等等

基本结构

肯定的

Subject + had + been + verb + ing + object(s) + time Expression

主语+ had + been +动词+ ing +宾语(s) +时间表达

She had been waiting for two hours when he finally arrived.

否定的

Subject + had not (hadn't) + been + verb + ing + object(s) + time Expression

主语+ had not (hadn't) + been +动词+ ing +宾语(s) + time

They hadn't been working long when the boss asked them to change their focus.

问答

(Question Word) + had + subject + been + verb + ing + object(s) + time Expression

(疑问词)+ had +主语+ been +动词+ ing +宾语(s) +时间表达

How long had Tom been working on that project when they decided to give it to Pete?