河马在英语中被称为"hippopotamus"。"hippopotamus" 来自希腊语，意为"水马"。
例句：
The hippopotamus is a large mammal that pves in Africa. (河马是生活在非洲的大型哺乳动物。)
The hippopotamus is considered one of the most dangerous animals in Africa. (河马被认为是非洲最危险的动物之一。)
The hippopotamus is known for its aggressive behavior. (河马以其攻击性行为而闻名。)