reason后的同位语从句只能由that引导，而定语从句可以由that、which、why等引导。
从句由that引导时，that在同位语从句中不作成分，从句本身结构即是完整的；而that在定语从句中作名词性成分如主语、宾语、表语。
The reason (that) he told us was not true.
他告诉我们的理由不是真的
I don\'t know the reason why she hates me.
我不知道她为什么恨我
Give me a reason which could satisfy my curiosity.
给我个理由来满足我的好奇心吧
