鲁达 1、一般情况在词尾加-s：map-maps, car-cars, girl-girls.
2、以s, x, ch, sh结尾的名词后加-es: class-classes,box-boxes, watch-watches, dish-dishes
3、以-f或-fe结尾的词：变-f和-fe为v再加-es:leaf-leaves, thief-thieves, knife-knives, loaf-loaves
加-s：belief-beliefs, chief-chiefs, proof-proofs, roof-roofs, gulf-gulfs
4、以辅音字母加y结尾的名词，变y为i加-es：party-parties, family-families, story-stories, city-cities
6、以辅音字母加-o结尾的名词：
一般加es: hero-heroes, negro-negroes, potato-potatoes, tomato-tomatoes,mago-magoes
两者皆可:zero-zeros/zeroes, volcano-volcanoes/ volcanos
7、改变名词中的元音字母或其他形式：man-men, woman-women, foot-feet, goose-geese,mouse-mice
8、单复数相同：sheep, deer, series, means, works, fish
9、只有复数形式：ashes, trousers, clothes, thanks, goods, glasses, compasses, contents
10、一些集体名词总是用作复数：people, police, cattle
11、部分集体名词既可以作单数（整体）也可以作复数（成员）：audience, class, family, crowd, couple, group, committee, government, population, crew, team, public, enemy, party
数量词hundred, thousand, million,doze等用单数: 100 hundred tons. 但是加of用复数:hundreds of tons
12、复数形式表示特别含义：customs(海关), forces(军队), times(时代), spirits(情绪), drinks(饮料), sands(沙滩), papers(文件报纸), manners(礼貌), looks(外表), water(水域)
13、表示“某国人”：加-s:Americans, Australians, Germans, Greeks, Swedes, Europeans
单复数同形:Swiss, Portuguese, Chinese, Japanese;
以-man或-woman结尾的改为-men,-women:Englishmen, Frenchwomen
14、以a结尾的复数： medium-media 媒体、媒介 bacterium-bacteria 细菌
15、合成名词:将主体名词变为复数:sons-in-law, lookers-on, passers-by, story-tellers, boyfriends
无主体名词时将最后一部分变为复数:grown-ups, housewives, stopwatches
将两部分变为复数: women singers, men servants
16、复合名词作定语：ten-year-old, ten years old.
摘自：《词老大高中英语-仅此而已》
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