Question

the reason why定语从句中,为什么名称后面是一个原因状语,

Answer 1

eason后跟什么引导词取决于reason在后面的从句中作什么成分,做状语的的自然用why,作宾语或者主语的话用which或者that,例如,

the reason why he didn't come was that he was ill.

the reason that /which he gives to me is that he is ill.