The single most important factor ______ contributes to success is ______ you do every single day．
A.that,that
B.which,what
C.which,what
D.that,what
网友回答
D解析从句子结构分析,第一个空考查定语从句的关系词,因先行词前有形容词最高级修饰且指事物故只用that引导;第二个空跟在be动词后,表明是一个表语从句,用do后缺少宾语,因此只能由what来引导。