(单选题)

What does the phrase a roller-coaster ride in the first paragraph mean? ( )

A.It means America has gone through a sense of changes that were not planed.

B.It means the tradition from an equal to unequal society turns out to be surprising.

C.It means it has met many difficulties and obstacles to reach the equality.

D.It means the inequality has developed in an uneven way instead of straight way.

参考答案：B

参考解析：

由第一段的United States go from being the most egalitarian country in the West to being one of the most unequal可知，美国社会从平等到不平等这一变化就像过山车一样，令人惊讶。故本题正确答案选B。

知识点：含义题英语阅读理解通用英语