The risorius and the buccinator muscles assist in the retraction of the lips, as well as support entrapment of air within the oral cavity.
笑肌和颊肌帮助唇的收缩，也支撑了整个口腔的气体流通。
The risorius and the buccinator muscles assist in the retraction of the lips, as well as support entrapment of air within the oral cavity.
笑肌和颊肌帮助唇的收缩，也支撑了整个口腔的气体流通。
声明：以上例句、词性分类均由互联网资源自动生成，部分未经过人
，其表达内容亦不代表本软件的观点；若发现问题，欢迎向我们指正。
