youll be able to succeed mainly depends on you do and you do it.A. If; what; whyB. Whe

问题补充：

youll be able to succeed mainly depends on you do and you do it.

A. If; what; why

B. Whether; how; why

C. That; whether; how

D. Whether; what; how

答案：

A. If; what; why

B. Whether; how; why

C. That; whether; how

(答案→)D. Whether; what; how

解析：考查名词性从句。分析句子结构可知,第二空应该是做do的宾语,引导on后面的宾语从句,只能用what,第三空应该是do it的方式状语,用how,那么第一空则应该是个主语从句,一般疑问句改成主语从句只能用whether引导,不能用if。