as other true likely networks include help by last who member fr

as other true likely networks include help by last who member friend In traditional societies, everyone in the community is related to everyone else, either as biological relatives or in-laws. In post-industrial societies, this is no longer _51 _—we live among strangers, some of whom become friends. As a result, our social circles really consist of two separate _52_—family and friends—with roughly half drawn from each group. Because the pull of kinship(亲属关系) is so strong, we give priority to family, choosing to _53_ them in our networks above unrelated individuals. Indeed, people _54_ come from large extended families actually have fewer friends. One reason we favor kin is that they are much more _55_ to come to our aid when we need _56_ than unrelated individuals, even if these are very good friends. Family and friend relationships differ in _57_ important ways, too. One is that friendships may not _58_ very long if untended. Failure to see a _59_ for six months or so leaves us less emotionally attached. Family relationships, _60_ contrast, are incredibly resilient(能复原的) to neglect. As a result, the family half of our network remains constant throughout most of our lives whereas the friendship component undergoes considerable change over time.


10. _____
【正确答案】：by