必修2 Unit 5　Music 课前是10分钟 概括大意 Most families consist of a mother，a father，and，at most，two children living at home.There may be relatives—grandparents，aunts，uncles，cousins living in the same community，but American families usually maintain separate households.This family structure is known as the “nuclear family”.It is unusual for members of the family other than the husband，wife，and children to live together. 此段落的大意是：Usual family structure of American families.