Everyone has his or her advantages and only you do best can help to reach the goal and t

问题补充：

Everyone has his or her advantages, and only you do best can help to reach the goal and truly make a difference.

A. discovering what

B. discovering whose

C. by discovering what

D. by discovering which

答案：

(答案→)A. discovering what

B. discovering whose

C. by discovering what

D. by discovering which

解析：考查动名词做主语和宾语从句用法。本题中的动名词短语discovering what you do best在句中做主语，之中含有宾语从句what you do best，其中what作为do的宾语。句意：每个人都有自己的优点，只有发现了你最擅长做的事情才能够帮助实现目标，真正地起作用。故A正确。