--s:bird,shop,lake,dog,sea

　　ch,sh,s,x--es:church,dish,class,box,watch

　　y--ies:factory,fly,family,baby,university

　　o--es:tomato,hero,potato,echo,domino

　　f,fe--ves:leaf,thief,shelf,knife,life

　　f,fe--s:belief,cliff,gulf,proof,fife

　　o--s:piano,photo,memo,solo,soprano

　　不规则变化：tooth--teeth,foot--feet,goose--geese,ox--oxen,mouse--mice

　　单复数同行：cattle,means,deer,fish,bison