有膝状关节的

例句：

1. 1.She sat down on the couch with her knee on the armrest.
   她坐在沙发上，膝盖搁在扶手上。
2. 2.The child's knee was bleeding after falling off the bike.
   孩子从自行车上摔下来后膝盖流血了。
3. 3. He knelt down to tie his shoelaces.
   他跪着系鞋带。