以什么结尾的单词变复数加es

　　1.以s,x,ch,sh,z结尾的单词后加es,例如,bus-buses;watch-watches;

　　2.以辅音字母加y结尾的,把y变i加es,例如,baby-babies,lady-ladies;

　　3.部分以o结尾的单词后加es,例如,potato-potatoes,hero-heroes;

　　4.一般以f和fe结尾的单词要把f,或fe变为ves,例如,wife-wives,knife-knives;