Every month he sets ___ a sum of money for old age.

题目

Every month he sets ___ a sum of money for old age.
a.apart
b.aside
c.in
d.up
请问选哪个?选和不选的原因?顺便把句子翻译成中文.

答案

选B.set sth aside 把什么留出来.
set apart 隔离,使突出
set up 建造
set in 没听说过这种用法.
每个月他都会留出一笔钱以作养老之用.