一、规则变化
一般在词尾+s:book - books,egg - eggs
以辅音字母+y结尾的词,把y改为i+es:city - cities,country - countries元音字母+y结尾的词,直接+s:boy - boys,monkey - monkeys
以f或fe结尾的词,把f或fe改为v+es:leaf - leaves,knife - knives
(1)有些加es:tomato - tomatoes西红柿,potato - potatoes土豆,hero - heroes英雄,Negro - Negroes黑人(一般认为是有生命的加es,但不是绝对的,还有一些有生命的以o结尾的词加s。)(2)有些加s:piano - pianos钢琴,radio - radios收音机,photo - photos照片,zoo - zoos动物园,kangaroo - kangaroos袋鼠,bamboo - bamboos竹子,hippo - hippos河马
二、不规则变化
以man和woman为基础的单词,把a变成e:man - men,woman - women,policeman - policemen,policewoman - policewomen,postman - postmen(注意:German德国人 - Germans)