which和who能否充当定语从句的先行词

见过that充当先行词的状况（高中课文里有个句子：That wasnt a real diamond necklace you borrowed from me.课本注解说，you borrowed from me是定语从句，修饰that)。

不了解which和who能否充当定语从句的先行词。

Who did he recommended that you thought was not competent for the job?

他推荐了哪个你感觉不胜任工作？

What did he give you that you sold to Tom? 他给你的什么东西你卖给了汤姆？

Which did he give you that you sold to Tom? 他给你的了哪一个你卖给了汤姆？

这都是我一个人写的句子。我感觉是没问题的。