常见例句when the upper lip is connected to the snout by a frenum, the two are continuous and the upper jaw is restricted from being protractile; 上嘴唇被一个系带连接到吻部，两者是连续的，而上颌则是被局限不能伸出的；protractile limbs and claws. 可伸展的肢体和爪子 返回 protractility