that, because, whyThe reason ____ he didn't come was ____ he was

that, because, why
The reason ____ he didn't come was ____ he was injured.
【正确答案】：why;that
【题目解析】：【考点点击】本题考查关系词的选择。【要点透析】why引导一个定语从句,在从句中作状语,定语从句中不缺成分,所以第一个空处不用that;第二个空是that引导的表语从句,主语是 reason时,不能用 because引导表语从句,要用that