By contrast, a popular culture is a large heterogeneous group, often highly individualistic and constantly changing.

22.What does the author imply about the United States and Canada?

(A) They value folk cultures.

(B) They have no social classes.

(C) They have popular cultures.

(D) They do not value individualism.

原文谈到folk culture 和popular culture两种文化，它们之间形成对比。既然美国和加拿大不再存在folk culture，那么它们就有popular culture。因此（C）为正确答案。

例二：

Both the number and the percentage of people in the United States involved in nonagricultural pursuits expanded rapidly during the half century following the civil war, with some of the most dramatic increases occurring in the domains of transportation, manufacturing, and trade and distribution.

What can be inferred from the passage about the agricultural sector of the economy after the Civil War?

(A) New technological developments had little effect on farmers.

(B) The percentage of the total population working in agriculture declined.

(C) Many farms destroyed in the war were rebuilt after the war.

(D) Farmers achieved new prosperity because of better rural transportation.

文中指出：非农业人口的数量和比例都增加了。由此可知农业人口的数量和比例下降了。所以（B）为正确答案。