※ 引述《moneyred (..)》之铭言：
: DENVER — One of three suburban Denver girls who authorities say tried to
: join Islamic State militants in Syria was confused about what her role would
: be if she had actually made it there, the girl's father said Tuesday.
: 请问此处的who authorities，我感到疑惑的是
: (1) authoritity 不是只有名词解吗? 如果用法是who authorities 不就怪怪的?
: (2) 此处who authorities 是做如何解呢?
: 以上，谢谢指点
就我理解的说说看
请其他人指点
原本应该是:
One of three suburban Denver girls (who authorities say [that she tried to join Islamic State militants in Syria]) was confused about...
()内是"One" of three suburban Denver girls的关系子句
[]内是名词字句，say的受词
that省略
she被who取代