这句话常用,记住它：
As every coin has two sides……
类似说法还有：
Evey medal has two sides.
每个勋章都有两面./每个问题都有正反两面.凡事有利弊
As a popular saying goes, everything has two sides.
常言道：事情总是一分为二的.
There are always two sides to a coin.
凡事都存在正负二个方面.
顺便提及：
1.双刃剑Double-edged sword或者double blade sword.
At the very start, athletic sport is a double blade sword.
竞技体育从一开始,就是一把双刃剑.
2.权衡利弊 weigh the advantages and disadvantages