在全世界，甚至在同一個社會中，家庭結構有著不同的形式。家庭的構成形式隨著不斷變化 的社會和經(jīng)濟影響而改變。直到最近，北美洲最普遍的家庭形式為核心家庭，由一對夫婦和他們 未婚的孩子構成。核心家庭是一個獨立的單位。它必須能夠照料自己。家庭成員緊密依賴著彼此。 在緊急情況下，外界提供給家庭的幫助微乎其微。核心家庭中，只有當條件允許的時候，才會照 料家中年長的親屬。在北美洲，老人很少和家人一起生活，他們‘般住在退休社區(qū)和養(yǎng)老機構。
在工業(yè)社會，例如北美洲，核心家庭之間有很多相似點。在居住在惡劣環(huán)境中的因紐特人的 社會中，家庭間也有很多相似點。核心家庭結構良好地適應于流動性的生活。在惡劣的條件下， 流動性能讓一個家庭吃飽飯。對北美洲人來說，找工作和提高社會地位同樣需要流動性。
核心家庭并不總是北美洲人的標準。在農(nóng)業(yè)社會時期，小型的`核心家庭經(jīng)常是大家庭的一部 分。其中可能包括了祖父母、父母、兄弟姐妹、叔伯、阿姨以及表兄弟姐妹。在現(xiàn)在的北美洲， 單親家庭的數(shù)目大幅度增加。由核心家庭構成的單親家庭的數(shù)目是美國由于離婚、分居或者未婚 導致的單親家庭的兩倍。不僅在北美洲，在世界范圍內，家庭結構都會隨著不斷變化的條件而改變。

The Family

The structure of a family takes different forms around the world and even in the same society. The family's form changes as it adapts to changing social and economic influences. Until recently, the most common form in North America was the nuclear family，consisting of a married couple with their minor children. The nuclear family is an independent unit. It must be prepared to fend for itself. Individual family members strongly depend on one another. There is little help from outside the family in emergencies. Elderly relatives of a nuclear family are cared for only if it is possible for the family to do so. In North America，the elderly often do not live with the family ; they live in retirement communities and nursing homes.

There are many parallels between the nuclear family in industrial societies，such as North

America，and of families in societies such as that of the Inuits，who live in harsh environments. The nuclear family structure is well adapted to a life of mobility. In harsh conditions，mobility allows the family to hunt for food. For North Americans，the hunt for jobs and improved social status also requires mobility.

The nuclear family was not always the North American standard. In a more agrarian time，the small nuclear family was usually part 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 single-parent households. Twice as many households in the United States are headed by divorced，separated，or never-married individuals as are comprised 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.

詞匯:

nuclear /'nju:kh/ adj. 原子核的，中心的 harsh /ha:?/ n. 嚴酷的

emergency /I'm?:d??nsI/ n. 緊急狀況 agranan / ?'gre?rl?n/ adj. 土地的，耕地的