why在句中是关系副词,引导定语从句,修饰先行词reason,同时它在定语从句中作状语,此时why = for which,但要注意:关系词在定语从句中做主语或宾语时,要用关系代词that或which. The reason why/for which(也可以省去) he was late was that he got up late. 他迟到的原因是他起床晚了. The reason that/which/(也可以省去) he gave you was reasonable. 他给你的理由是合理的. (并非原创...)
说语法可能不太好懂,举个例子吧。这就是他为什么迟到的原因:This is the reason why he came so late. 这就是他说的原因:This is the reason that he said. 看翻译容易些,可以翻出“为什么…的原因”就用why,不能这样翻就当普通先行词处理,用that。希望你能明白~希望能帮助你~...