【正文】
the small nuclear family was usually pare of a larger extended family. This might have included grandparents, mother and father, brothers and sisters, uncles. aunts, and cousins. In North America today, there is a dramatic rise in the number of singleparent households. Twice as many households in the United States are headed by divorced, separated or nevermarried individuals as are prised of nuclear families. The structure of the family, not just in North America. but throughout the world, continues to change as it adapts to changing conditions