采煤机电缆夹的长度应为采煤机运行长度的()或略长一些(约长2~4米)。 ["全部","一半","三分之二","四分之三"]
()的过渡阶段是俱乐部婚姻。 ["母系社会到父系社会","群婚到族婚","母系社会到家庭社会","群婚到个体"]
盐的当量=盐的分子量/盐分子中金属原子数金属价数。()
银行受理客户提交的电汇凭证,其回单上应加盖() ["业务公章","结算专用章","清讫章","受理凭证专用章"]
()在中国泸沽湖畔实行走婚制。 ["索伦族","毕苏族","摩梭族","绕家人"]
社会情感