教的是过去完成时:
1.概念:以过去某个时间为标准,在此以前发生的动作或行为,或在过去某动作之前完成的行为,即“过去的过去”。
2.时间状语:before, by the end of last year(term, month…),etc.
3.基本结构:had + done.
4.否定形式:had + not + done.
5.一般疑问句:had放于句首。
6.例句:As soon as we got to the station, the train had left.
By the end of last month. We had reviewed four books
http://baike.baidu.com/view/238614.htm#6这里有完整的时态。
可以去看看。。如果实在看不懂还是问老师吧!
参考资料:http://baike.baidu.com/view/238614.htm#6
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