想法 二: 雪橇撞到地面突起物时,凯萨琳掉下来了.Idea 2 : Kathleen falls off the sled when it hits a bump.在开采洞穴时,你必须要戴上安全帽,以防止头部撞到突起物,或者被掉落的岩石砸伤.You should wear hard hats when caving to protect the head from bumps and falling rocks.息肉: 具黏膜的腔壁上形...

“突起物”的英语可以翻译为：[医]prominence ...