题干
If you see any litter on the school playground, you'd better _______.
A：give it away
B：pick it up
C：turn it off
D：put it on
答案(点此获取答案解析）
B
If you see any litter on the school playground, you'd better _______.
A：give it away
B：pick it up
C：turn it off
D：put it on
，那么
的最小值是 （ ）