It's a great feeling to think you're a small part of the reason that a kid decided to give school another try instead of dropping out or that a kid had the strength wp walk away whe someone offered him drugs.

the reason that 后面应该是同位语吧？为什么教材后面却说reason是先行词，难道是定语从句?

【答】在the reason that a kid decided to give school another try中， that a kid decided to give school another try 是定语从句。reason之后没有同位语从句，只有定语从句。that是关系副词，等于why，还可以省略。讲解如下：

1. 在定语从句中，why 指原因或理由，它的先行词只有reason，在定语从句中作原因状语。

why是关系副词，本身没有词汇意义，只起引导定语从句的作用，可以省略，也可以用that代替。例如：

Please tell me the reason why you were absent. 

Please tell me the reason that you were absent.

Please tell me the reason you were absent.

2. 但是，在下面的句子中，the reason也是先行词。不同的是，that是关系代词，在定语从句中作主语，因为缺少主语成分。

Please tell me the reason that/which made you absent.

在下面的句子中，the reason也是先行词。不同的是，that是关系代词，在定语从句中作宾语，因为缺少宾语成分。

Is this the reason that/which he gave us for being late? 这就是他给我们说的迟到的原因吗?

I won’t listen to the reason that/which you have given us. 我坚决不听你给我们提供的那个理由。