The reason why he didn't come to school was he was ill.A. thatB. howC. whyD. because

问题补充：

The reason why he didn come to school was he was ill.

A. that

B. how

C. why

D. because

答案：

(答案→)A. that

B. how

C. why

D. because

解析：考查表语从句，当主语是the reason的时候，表语从句用that连接，句型是the reason why…is that….，…的原因是什么…，句意：他为什么没来学校的原因是他病了。选A。