乳牙知识
张昔
You sleep at night with your milk tooth beside your bed or under your pillow for the tooth fairy to come and take it and give you a gift in return. Ever wondered why do you have these brittle1milk teeth, which we lose as we grow up?晚上睡觉时,你把乳牙放在床边或枕头下,让牙仙来取走它,并给你一份礼物作为回报。你有没有想过为什么你会有这些随着年龄的增长而换掉的易碎的乳牙?