问题
选择题
The reason ______ most Chinese have healthy white teeth is ______ they eat a healthy diet.
A．why; that
B．why; because
C．that; that
D．for; that
答案
答案：A
考查定语从句及名词性从句。句中why引导定语从句，先行词the reason在从句中作原因状语；that引导表语从句，故选A。