The reason (why/that) he failed was his laziness. 如果是why的话定从,that的话同位,是否正确?

一、the reason why肯定是定语从句二、the reason that 不一定都是定语从句,分以下两种情况 1.当that后面加的句子是完整的句子的话,那它肯定是同位语从句,例如 He gave me the reason that he got up too late t...The reason that he failed was his laziness.这句话应该不对 the reason for which he failed was his laziness 如果是that的话，感觉说不通你说的对，定语从句中，the reason做先行词时，引导词更多的用why，或用for which，而that多出现在同位语从句中，The reason that he failed was his laziness.这是同位语从句，根据同位语从句的含义，应该是对前面的词进行补充说明，而本句是起修饰限定的作用，所以应该是定语从句，而从句部分并不缺主语、宾语或表语，所以只能选择关系副词why（=for which），做状语。