(1)一般情况直接在词尾加"-s",如:cake-cakes,bag-bags,day-days,face-faces,orange-oranges等;
(2)以s,x,sh,ch结尾的词,要在词尾加"-es",如:bus-buses,watch-watches,box-boxes等;
(3)以辅音字母加y结尾的词,变y为i再加"-es",如:baby-babies,country-countries,family-families等;
(4)部分以f(e)结尾的词,变f(e)为"ves",如:knife-knives,half-halves等;
(5)以o结尾的词,加"-s"或"-es",如:zoo-zoos,photo-photos,tomato-tomatoes,potato-potatoes等。记忆口诀:除了"英雄"hero外,凡是能吃的,加"-es",不能吃的加"-s"。