any of the 32 teeth that replace the deciduous teeth of early childhood and (with luck) can last until old age
例句
用作名词 (n.)
The exfoliation of the deciduous teeth is mainly brought about by resorption of their roots and enhances by growth and eruption of the succeeding permanent teeth. 总而官之，乳牙之所以会脱落主要在于它们的根部会发生吸收，而其下正在萌出的永久齿则增进了它在根部进行吸收的工作。
美
