《新概念英语》同步讲义：第2册第38课
【往期回顾】
【第2册第38课讲义】
本课的重点语法是过去完成时。
过去完成时表示在过去某一时间或动作之前已经发生或完成了的动作，即“过去的过去”，其基本结构为：had done。过去完成时的主要用法可参考第14课。
过去完成时常见的时间状语有：
1、 by+过去时间点。如：
He had arrived in Paris by last Friday.
2、 by the end of+过去时间点。如：
By the end of last week, he had stayed in the city for ten days.
3、 Before+过去时间点。如：
They had already come back home before last Saturday.
此外，经常使用过去完成时的两个重要句型有：no sooner…than…和hardly…when…。如：
I had no sooner got home than it began to rain heavily.I had hardly got home when it began to rain heavily.
以上两句话中的否定副词或短语hardly和no sooner如果提到句首，会引起倒装，即：
No sooner had I got home than it began to rain heavily.Hardly had I got home when it began to rain heavily.
本课的难点部分出现了几组词语的辨析：
1、country与countryside
两者都可以表示“乡村”，但是country另外一个比较常用的意思是“国家”。如：
He sold the house and left the country.他把房子卖了，离开了这个国家。The countryside around Vienna is very beautiful.维也纳周边的乡村非常漂亮。
2、continuously与continually
两者都有“持续”的含义，但是continuously表示“持续不断地”，continually表示“断断续续地”。如：
It has rained continually for one week.一周以来，一直在断断续续地下雨。The river flows under the bridge continuously all the year round.河水常年不停地从桥下流过。