这些动词均含有“攀登，上升”之意。
ascend ：正式用词，指不用手攀，一直上升直到相当高的地方。
- Mist ascended from the valley.
薄雾从山谷升起。 - The air became colder as we ascended.
随着我们往上攀登，空气就寒冷起来。
climb ：普通用词，含义广泛，侧重运用手足费力地攀登或上升，也可指抽象事物。
- The boys climbed over the wall.
那些男孩翻过了那堵墙。 - As they climbed higher, the air became cooler.
他们攀登得越高，空气就变得越凉爽。
mount ：书面用词，词义与ascend相近，强调连续不断地向上移动、攀登或上涨。指骑马时用mount。
- She slowly mounted the steps.
她慢慢地爬上台阶。 - He mounted his horse and rode away.
他骑上马走了。 - The death toll continues to mount.
死亡人数持续增加。
