The traditional view is _______ we sleep because our brain is “programmed” to make us do so.
A、when
B、why
C、whether
D、that
【正确答案】：D
【题目解析】：that引导表语从句，在从句中只起连接作用，不作任何成分。we sleep because our brain is “programmed” to make us to so是一个完整的句子，所以要用that引导。when和where在表语从句中作状语，分别表示“在……的时候”和“在……地方”。whether意为“是否”。
