腰板

例句：

1. 1. He sat down on the couch with his back against the wall.
   他坐在沙发上，背靠着墙。
2. 2. She stood up and stretched her back.
   她站起来，伸展背部。
3. 3. The doctor advised him to exercise regularly to maintain his back health.
   医生建议他定期锻炼以保持背部健康。