问题
单项选择题
Why does the author mention the Eastern Corridor and the California coast in Paragraph 4
A．As examples of megapolises.
B．Because 75 percent of the population lives there.
C．To conclude the passage.
D．The Bureau of the Census is located there.
答案
参考答案：A
解析：[分析] 细节题型。 根据第四段的the Bureau reports more than 280 MSAs， which together account for 75 percent of the US population，即75%的人住在MSA，但不单是the Eastern Corridor，California coast地区，因而排除B。第四段是对megapolis的介绍，不是对文章的总结，排除C。选项D的内容没有在文中提到。