Nuclear family may consist of ______.

W: I heard that your family arrived yesterday, didn’t they?
M: Yes, they did.
W: That’s good! Dr. Morrison, your family is now in China with you. You won’t miss them, then. To talk about the family, I want to ask you some questions about American families. Er... Do most Americans live in "small families" or "big families?"
M: In the United States, most people normally choose to live in "small families," but we call them "nuclear families."
W: What is the average size of a nuclear family?
M: Well, it depends on the number of children, because the nuclear family consists of a husband, a wife and children. However, if there are no children, then the husband and wife are the nuclear family. Of course, there maybe only one parent due to a death, separate or divorce. In this case, the nuclear family is the single parent and children.
W: Are there any big families in the United States?
M: Oh, you mean the extended family. No, not many. Most Americans, both the elderly and the young couples prefer to live in their own homes.
W: Since most Americans live in nuclear families rather than in extended families, the majority of the elderly do not see their children and their relatives, do they?
M: Well, people often make such assumptions, but that is not the case according to recent sociological research.
W: Oh, what’s that?
M: The recent research shows that more elderly people in the United States live within ten minutes of their children by car than in Denmark, and over 78 percent of the elderly had seen their children within a week.
W: Now I’ve got a general idea about American family structure. Thank you.
M: You’re welcome.