定语从句do you know the reason why he didn't come?为什么可以用why?从句后he是主语,didn't come是谓

问题描述:

定语从句do you know the reason why he didn't come?为什么可以用why?从句后he是主语,didn't come是谓
语,不是缺宾语吗?那怎么还可以用why

英语中规定:定语从句中的先行词reason 一律用 why做其引导词.
come 是不及物动词,后面不需要加宾语