As Benjamin Franklin put it, “A house is not a home it contains food and fire for the mind as well as the body. ”
A. since
B. as
C. once
D. unless
网友回答
A. since
B. as
C. once
(答案→)D. unless
解析：考查状语从句。句意：正如本杰明富兰克林所说的，“如同没有思想的躯体不能叫做人一样，没有食物和炉火的房子也不能叫做家。”A因为；B当；C一旦；D除非，相当于if not。这里表示的是条件，故选D。