joints of upper limb girdle

例句：

1. 1. The joints of the human body are designed to allow movement.
   人体的关节设计用来允许运动。
2. 2. The car's engine has several joints that need to be lubricated regularly.
   汽车的引擎有几个需要定期润滑的接合处。
3. 3. The scientist discovered a new method for treating arthritis by using natural compounds.
   科学家发现了一种使用自然化合物治疗关节炎的新方法。