问题补充：
Great changes have been made in family life because of science and industry. In the past, when more Americans lived on farms, the typical family had many children. In a farm family, parents and their children often lived with grandparents. Often, too, uncles and aunts lived nearby. But when industry becomes more important than agriculture in American life, families become smaller because industry requires workers who are ready and able to move off the land and to move again whenever necessary. And large families cannot be moved from place to place as easily as smaller families can. So , at present people tend to have smaller families.
In the future, because of industrialization, a typical family will be required to move even more often than now, so families will be even smaller. The typical families may remain childless and are only made up of a man and a woman. A small number of families may take raising children as their chief work. At the same time they may also raise other people’s children, leaving those families free to move job to job.
61. The main topic discussed in the passage is .
A. the development of science and industry in America
B. the influence(影响) of science and industry on America families.
C. the harmful effect of industrialization
D. the social problems resulting from the highly developed science and industries in America
62. are described in the passage.
A. Families of the past
B. Families of the present and of the future
C. Families of the past and of the future
D. Families of the past, the present and the future
63.According to the writer, one of the reasons that families are getting smaller in American is that .
A. children tend to leave their parents and grandparents when they grow up
B. people stop caring for having children
C. the need for workers who are able to move any time has been increasing
D. both old and young people like to live by themselves
64. will be in charge of raising children in the future.
A. most families B. all families C. social workers D. a small number of families
65. From the passage, we can conclude that .
A. science and industry have caused thousands of families to separate
B. children do not like to live with their parents or grandparents
C. large families can hardly exist in modern society
D. Americans are very careful in choosing their jobsB
答案：
(答案→)B
解析：
