human 通常以複數形式出現，較少使用單數形式的 a human。與較少使用單數形式的 a human 相比，單數形式的 a human being 則相對較為普通。human的使用：Humans have large brains. 人類腦子大。The drug has not been tried out on humans yet. 這種藥尚未經過人體試驗。Dogs can smell much better than humans. 狗的嗅覺比人強得多。Intellect distinguishes humans from other animals. 人類與禽獸之別在於人具有思維能力。Humans and dogs are mammals, but birds and fish are not. 人和狗都是哺乳動物，但鳥和魚不是。偶爾也用 a human，但並不多見。如：Its rate of growth was fast — much more like that of an ape than that of a human. 它的發育速度很快——更像猿，而不像人。human being的使用：I’m a human being. I can stand on my own feet. 我是人，我可以自立。I could never forgive her as a human being. 作為一個人，我永遠不能寬恕她。當然複數形式的 human beings 更為普通。如：Will it work on human beings? 這將對人有影響嗎？Human beings are creative animals. 人類是有創造力的動物。Men, women, and children are human beings. 男人、女人、孩子都是人。Ability to talk distinguishes human beings from the lower animals. 用語言交談的能力使人類有別於低等動物。It may be feasible to clone human beings, but is it ethical? 複製人類也許可以做到，但是這合乎道德嗎？順便說一句：human 或 human being 指人時，通常有（或暗示）與神、動物、機器人等相對比的意味，如果沒有這種對比，則較少使用，如一般不能說：How many humans [human beings] are there in your family? 你家裡有幾個人? (宜改用 people)
human 與 human being 意思相同，均表示“人”，但是用法上有區別：
human 通常以複數形式出現，較少使用單數形式的 a human。與較少使用單數形式的 a human 相比，單數形式的 a human being 則相對較為普通。human的使用：Humans have large brains. 人類腦子大。The drug has not been tried out on humans yet. 這種藥尚未經過人體試驗。Dogs can smell much better than humans. 狗的嗅覺比人強得多。Intellect distinguishes humans from other animals. 人類與禽獸之別在於人具有思維能力。Humans and dogs are mammals, but birds and fish are not. 人和狗都是哺乳動物，但鳥和魚不是。偶爾也用 a human，但並不多見。如：Its rate of growth was fast — much more like that of an ape than that of a human. 它的發育速度很快——更像猿，而不像人。human being的使用：I’m a human being. I can stand on my own feet. 我是人，我可以自立。I could never forgive her as a human being. 作為一個人，我永遠不能寬恕她。當然複數形式的 human beings 更為普通。如：Will it work on human beings? 這將對人有影響嗎？Human beings are creative animals. 人類是有創造力的動物。Men, women, and children are human beings. 男人、女人、孩子都是人。Ability to talk distinguishes human beings from the lower animals. 用語言交談的能力使人類有別於低等動物。It may be feasible to clone human beings, but is it ethical? 複製人類也許可以做到，但是這合乎道德嗎？順便說一句：human 或 human being 指人時，通常有（或暗示）與神、動物、機器人等相對比的意味，如果沒有這種對比，則較少使用，如一般不能說：How many humans [human beings] are there in your family? 你家裡有幾個人? (宜改用 people)