Sitting requires the muscles to hold the trunk, neck and shoulders in a fixed position.
坐着要求肌肉使躯干、颈部和肩部保持在固定的位置。
2
Because force is generated with help from the ground, bending your knees places your body in better position to produce trunk, hip, and shoulder rotation.
因为力量源自地面，弯曲你的膝盖能让你的身体处于一个更易通过躯干，髋和肩部转动获得能量的绝佳位置。
3
The freshwater transportation occupies an important position in the province and trunk railways radiates in all directions.