scratch'n'sniff
问题描述：
scratch'n'sniff
来源于一段关于情人节由来的英文短文.原句是：
The modern valentine card has become increasingly sophisticated,keeping pace with popular technological advances.For example,there are cards that let you record a romantic message,"scratch-and-sniff" cards and cards that play romantic music.
答
就是那种卡上会画个鼻子啥的,用手指挠它就会发出打喷嚏的声音；
还有的是挠了痒会咯咯笑的.