people表"人""人们",表单个人的时候本人已有复数意思,one people ,three people(不再加s)
如果不巧,你遇到了peoples,一般是表示民族了,比如中国的,fifty-six peoples
person表"一个人",也是特别常用的,注意复数问题.
one person three persons.
man一般以单数形式出现（现在也有人以复数men表示“人类”）,其前不能置任何限定词,其相应的代词应是he,him,his,himself.例如：The changes between the states have been used by man to work for him since ancient times.自古以来,人类就利用这两种状态的变化为自己服务.Engels pointed out a hundred years ago that labour created man himself.恩格斯一百多年以前就指出,劳动创造了人类本身.
mankind前也不可加任何限定词,但可用形容词修饰.它是集合名词,可作单数或复数使用.作单数概念时,谓语要用单数,其相应的代词一般为it,its,itself(也有人用he ,him,his,himself);作复数概念时,谓语要用复数,其相应的代词是they,them,their,themselves.例如：Mankind is much cleverer than it was one thousand years ago.人类比一千年前是聪明多了.All progressive mankind love peace.所有进步人类都热爱和平.That is one small step for a man,but one giant leap for mankind.对于个人来说那是小小的一步,但对于整个人类来说却是一次巨大的飞越.
请注意：human being也可表示“人类”,它是可数名词,有单复数之分.其意义比较具体,它一般用来区别人以外的事物,特别是动物或者是“神”,“鬼”之类.例如：Without its light and warmth there would be neither plants nor animals nor human beings.没有光和热,就不可能有植物,动物,也不可能有人类.Although the Negroes were human beings just like the whites,they were not treated as humanbeing.尽管黑人和白人一样都是属于人类,但是他们并没有被当作人对待.
