—What has made him look like lacking sleep?
— his wife is ill and he has to get up several times a night to attend to her.
A. For
B. Because
C. That
D. What
网友回答
A. For
B. Because
(答案→)C. That
D. What
解析：考察名词性从句关系词 句意为：---是什么导致他看上去缺乏睡眠呢
----他的妻子病了，他得每天起夜几次去照顾他生病的妻子
That做为名词性从句的引导词，起连接作用，本身无实际意义。从语法关系上看，that从句相当于名词的功能。根据上句what可判断，下句应是一个在语法上充当主语的句子成分。故C选项符合题意
考点:考察名词性从句关系词