1、直接加-s.
如: tree-trees树2、以s,x, ch, sh 结尾的加es.
如:bus-buses, box-boxes, watch-watches 手表, brush-brushes 刷子, glass-glasses.3、以辅音字母+ y结尾的,改y为i再加es.
如:country-countries 国家4、以f或者fe 结尾的词,改f为v,再加es.
如:knife-knives刀5、以O结尾的单词,有生命的+-es,无生命+s.
如:Hero-heroes 英雄, Negro-negroes 黑人, potato-potatoes 土豆, tomato-tomatoes 西红柿


