[解析]
52:C;细节理解题,由第一段的Here in London可知作者来自London,故选C.
53:D;段落大意题,根据第二段第一句The London Underground is very famous.It's famous for several reasons.可知该段讲述的是为什么The London Underground出名.故选D.
54:A;词汇猜测题,根据短文内容By the way,we don't use the word"subway"here.It's American English.We call it"the Underground",instead.和Thirdly but not the last,the London Underground is the second largest metro system in the world,after the Shanghai Metro.可知"subway","underground",and"metro"都是地铁的意思,答案选A.
55:D;细节理解题,根据最后一段第三句Maybe you can send me a few photos of your city today.可知作者想要洪波给他发一些照片;答案选D