2. All round
fingernail very easy desquamate, especially
fingernail left and right sides, be because, what?
手指甲周围很容易脱皮,特别是指甲左右,是因为什么呢?
3. The effect is easy to observe on a smooth, flat-black material(e. g. poster-painted paper), but you can see it on a
fingernail or a worn coin as well.
在一个光滑的、平而黑的材料上(例如招贴画的纸)容易看到这个效应,但是也可以在指甲上或旧的硬币上看到。