baby city country butterfly difficulty lady story family partyduty,copy,capacity,facility,labtory,library,responsibility,company,activity,autobiography等等,臨時想的也沒寫太多.以y結尾的名詞變複數時 a:子音字母+y結尾的名詞,將y改變為i,再加es baby-babies family-families pony-ponies city-cities country-countries b:母音字母+y結尾的名詞,名詞後加一個s valley-valleys donkey-donkeys toy-toys boy-boys guy-guys這樣你就不用記那些單詞具體是什麼了複數名詞以子音字母+y結尾的詞，變y為i加es的有：baby（嬰兒）-babies, university（大學）-universities, fly（蒼蠅）-flies, impurity（雜質）-impurities.補充單數名詞變複數名詞的規則變化：

1. 一般在名詞詞尾加s。如：dog-dogs, house-houses, gram-grams.2. 以s,sh, ch及x結尾的名詞加es構成其複數形式。如： kiss-kisses, watch-watches, box-boxes, bush-bushes.3. 以o結尾，注意以下幾點：（1）一般在詞尾加es.如：tomato-tomatoes, potato-potatoes（2）如果是外來語或縮寫名詞, 則加s。如：piano-pianos, dynamo-dynamos, photo-photos, kimono-kimonos, biro-biros。（3）有些以o結尾的名詞,其o前是母音字母則加-s。如：studio-studios, radio-radios.（4）以oo結尾的名詞只加s。如：zoo-zoos。4. 下列以f或fe結尾的名詞，須先將f或fe改成v，再加es。這些名詞是：calf, half , knife, leaf, life, loaf,self, sheaf, shelf, thief, wife, wolf 等。如：wife-wives, wolf-wolves, calf-calves.5. 以下幾個名詞scarf, wharf, hoof, handkerchief等的複數形式，可先將f或fe改成v，再加es；也可直接加s，即scarfs或scarves, wharfs或wharves, hoofs或hooves, handkerchiefs或handkerchieves。