matters most in learning English is enough practiceA. WhatB. WhyC. WhereD. Which

问题补充：

matters most in learning English is enough practice．

A. What

B. Why

C. Where

D. Which

答案：

(答案→)A. What

B. Why

C. Where

D. Which

解析：考查主语从句的引导词。What引导起主语从句，并在句中做主语。句意：学习英语中最重要的是有足够的练习。