knuckle bushing

例句：

1. 1.He sat on the couch with his knuckle pads on.
   他坐在沙发上，膝盖上放着衬垫。
2. 2.The basketball player had to wear a knuckle pad to protect his knees.
   篮球运动员不得不戴上膝盖衬垫来保护他的膝盖。
3. 3. She put her knuckle pads on before she started running.
   她开始跑步前先穿上了膝盖衬垫。