Perfect posture: Tips for good posture include sitting with your bottom right at the back of the seat, and relaxing the shoulders so they don't elevate or become round
最佳姿势：最正确的姿势是紧靠椅子后背坐，肩膀放松，不要抬起或向前垂弯。
Vocabulary：
shoulder blade: 肩胛骨
spine: 脊柱
quad: 股四头肌