核心问题
a family which quarrel amongst themselves... 据说这里用 which 是错误的。a family which, a committee which, a group which 不是很常见的搭配吗？
词典解答
按照英语惯用法,当指人的集体名词(team, audience, crew, jury, public, committee, family)与复数动词连用(即集体名词不是表示整体而是表示组成人员)时,其关系代词应当是 who/whom,而不应当是 which。如使用 which,就必须与单数动词连用。
The London team, which played so well last season, has done badly this season. (Eckersley) 伦敦队上个赛季打得很好，这一赛季打得却很糟。