3．集合概念推理
集合概念推理也可以稱之為百分比推斷，它指的是在一個集合中，包含兩個相對的方面，共同構成一個大的集合。一方所占的比例減少意味著另一方所占比例的增加；反之，一方所占的比例增加意味著另一方所占比例的減少。根據(jù)這一思路，可以由集合中一方的數(shù)量變化推斷另一方的消減。
例一：
A folk culture is small, isolated, cohesive, conservative, nearly self-sufficient group that is homogeneous in custom and race, with a strong family or clan structure and highly developed rituals. …Unaltered folk cultures no longer exist in industrialized countries such as the United States and Canada….
By contrast, a popular culture is a large heterogeneous group, often highly individualistic and constantly changing.
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.
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.
集合概念推理也可以稱之為百分比推斷，它指的是在一個集合中，包含兩個相對的方面，共同構成一個大的集合。一方所占的比例減少意味著另一方所占比例的增加；反之，一方所占的比例增加意味著另一方所占比例的減少。根據(jù)這一思路，可以由集合中一方的數(shù)量變化推斷另一方的消減。
例一：
A folk culture is small, isolated, cohesive, conservative, nearly self-sufficient group that is homogeneous in custom and race, with a strong family or clan structure and highly developed rituals. …Unaltered folk cultures no longer exist in industrialized countries such as the United States and Canada….
By contrast, a popular culture is a large heterogeneous group, often highly individualistic and constantly changing.
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.
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.