问题补充:
For many cities in the world, there is no room to spread our further, New York is an example.
A. for which
B. in which
C. of which
D. from which
答案:
A. for which
B. in which
(答案→)C. of which
D. from which
解析:of which引导的间隔性非限制性定语从句, 对cities起补充、说明的作用。介词of的选择取决于和前面名词的搭配 of the cities。