选B set aside,她留出了一笔钱养老.
注意：这里的set是过去式,否则就要用sets了.
A set up 建立
She set up a company last year.她去年开了家公司.
C set in 开始；到来
Spring has set in.春天来了.
D set off 出发；动身
You should set off right now,or you'll be late.你最好现在就出发,要不就会迟到.