学习通tooth的复数形式是teeth，例如“I brush my teeth everyday except Sunday”的意思是除了星期天，我每天都刷牙。tooth作名词时意为牙齿，作动词时意为给……装齿、啮合。比如tooth profile：齿形；tooth decay：蛀牙等。
相关例句：1、You should pull out this tooth. 你必须把这颗牙齿拔掉。
2、In the morning my tooth is not there. But I find some coins! 早上的时候我的牙齿不在那了但是我发现了一些硬币。
3、I pictured him with a little one on his knee, helping her write her first letter to the Tooth Fairy. 我想象着有一个小宝贝坐在他的膝上，他抱着她，帮她给牙齿仙女写第一封信。