1. Is the chunk that black appears inside fingernail why? ָ��������ֺ�ɫ�Ĵ����Ϊʲô?
2. All round fingernail very easy desquamate, especially fingernail left and right sides, be because, what? ��ָ����Χ��������Ƥ���ر���ָ�����ң�����Ϊʲô�أ�
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. ��һ���⻬�ġ�ƽ���ڵIJ����ϣ�������������ֽ�����������ЧӦ������Ҳ������ָ���ϻ�ɵ�Ӳ���Ͽ�����