[fǎn miàn]
（与正面相反的一面） reverse side ; wrong side; back; verso
the reverse side of a disc
唱片的反面
the wrong side of the cloth
料子的反面
（坏的、消极的一面） opposite; negative side; as opposed to positive
negative role; villain
反面角色
a lesson learnt from negative experience
反面的教训
（事情、问题等的另一面） opposite; inverse; the other side of the matter
turn into one's opposite
走向反面
see the reverse as well as the obverse side of things
不但看到事物的正面， 也看到事物的反面
Evil is the inverse of good.
恶是善的反面。