问题
选择题
No one really knows for sure ________ makes a person become right-handed rather than left-handed.
A．whatever
B．who
C．what
D．whoever
答案
答案：C
题目分析：句意：没有人确切的知道什么使人们用右手而不是左手。这里know后面接的是宾语从句，宾语从句中缺少主语，用what连接宾语从句，whatever“凡是…的东西”，who“谁”，whoever“凡是…的人”，选C。