同学你好，该知识点来自沪江网校《新概念英语1、2、3、4册连读【学霸班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
wear down(使)磨平; (使)磨光
Pipe smokers sometimes wear down the tips of their teeth where they grip their pipes.
抽烟斗的人用牙齿咬住烟斗，有时会把齿尖磨平。

wear out(使)磨损; (使)用坏
Every time she consulted her watch, she wondered if the batteries were wearing out.
每次她看手表，都会怀疑是不是电池没电了。

wear away (使)磨薄
It had a saddle with springs sticking out, which wore away the seat of my pants.
鞍座上的弹簧翘出来，把我裤子臀部那块磨破了。

祝同学学习进步~