定语从句先行词是those
That(指物)和those(指人或物)可做定语从句的先行词，this和these不可做先行词，those做定语从句先行词时，当其指物关系词用that/which等，当其指人时，关系词用who等，具体示例如下：
He admired those who looked beautiful.他很喜欢那些看上去很美的人.(指人)
He admired those which looked beautiful.他很喜欢那些看上去很美的东西.(指物)
(错)He admired that who danced well.(that不能指人)
(对)He admired those who danced well.他赞赏跳舞好的人.(those可指人)
先行词是those引导词用什么
those后接定语从句时，通常用关系代词who来引导。如：
Those who do not wish to go need not go. 不愿去的人不需要去。
