reason定语从句

问题描述:

reason定语从句
Is that the reason ___ you are in favour of the poroasl?
A.whichB.what C.why D.for that
请帮我解答一下并说明理由,谢谢!
那什么时候用that?

选C
which用在先行词reason的后面一般为for which
what不用于定语从句
这种句式没有for that的用法
why=for which