重点讲解：
1. on earth
（用于以how， why， what 或 where 开始的问句，表示强调，通常表示问题没有答案或很难回答）究竟，到底；
eg. Where on earth did you get that?
你到底从哪里弄来的？
eg. Why on earth would he want to go to such a place?
他到底为什么想去那么个地方？
2. be curious about
求知欲强的；好奇的；
eg. Steve was intensely curious about the world I came from.
史蒂夫非常想了解我以前生活的那个世界。
eg.And I'm curious about the subject of your dissertation.
而且我对你的研究课题非常好奇。
3. quieten down
（使）安静；（使）平静下来；
eg. The labour unrest which swept the country last week has quietened down.
上周席卷全国的劳工暴动已经平息了。
eg. Somehow I managed to quieten her down.
我设法让她平静了下来。
