问题
单项选择题
The author's purpose is to ______.
A．give the basic facts of marriage in North America
B．explain the reasons why the divorce rate is high in North America
C．introduce why both husband and wife have to work outside their home
D．give a picture of family structural change in North America
答案
参考答案：D
解析：[分析] 主旨题型。 A、B、C项内容在第四段和第五段文中都有介绍，因而应选D。