名词的词形变化
1.不规则复数形式
1）来自古英语的复数形式，如：
child-children foot-feet tooth-teeth goose-geese
man-men woman-women mouse-mice louse-lice
ox-oxen penny-pence analys**-analyses appendix-appendices
parenthes**-parentheses bas**-bases ellips**-ellipses
ax**-axes hypothes**-hypotheses oas**-oases cr****-cr**es
criterion-criteria phenomenon-phenomena datum-data medium-media
bacterium-bacteria nucleus-nuclei fungus-fungi stimulus-stimuli
alumnus-alumni focus-foci radius-radii terminus-termini
larva-larvae alga-algae formula-formulae
当代美国英语中往往把data当做单数用，因此常见到复数形式datas。另外，lens是一个单数可数名词，其复数形式为lenses。1）词尾读音为[f]并以－f或0－fe结尾的名词复数形式有以下几种情况：
a）规则形式：
belief-beliefs chief-chiefs cliff-cliffs grief-griefs
b）不规则形式，即把－f或－fe变成－v，再加－es,读音为[vz]:
calf-calves half-halves leaf-le**es life-lives
loaf-lo**es self-shelves thief-thieves wife-wives
wolf-wolves
c）既可是规则形式又可是不规则形式：
dwarf-dwarfs/dwarves hoof-hoofs/hoves
scarf-scarfs/scarves wharf-wharfs/wharves
3）词干以－o结尾的名次有三种情况：
a）附属形式为－s：这类词包括缩略词kilos,photos；表示国籍或民族的词filipinos,eskimos以及radios,solos,sopranos,
studios
b）复数形式为－es，如：heroes,potatoes,tomatoes,negroes。c）复数有规则的和不规则的两种形式，如：
cargo-cargos/cargoes mosquito-mosquitos/mosquitoes volcano-volacbos/volcanoes
2.单复数同形的名词
1）某些动物名词，如：deer,grouse,salmon,trout,carp,b**on,sheep等
2）以－ese或－ss结尾的表示民族或国籍的名词，如：chinses,japanese,portuguese,sw**s,vietnamese等
3）某些以－s结尾的名词，如：barracks,corps,crossroads,gallows,headquarters,means,series,species,works等
4）某些表示计量单位的名词，如：horsepower,hertz,kilohertz,li,mu等
其他一些名词，如：aircraft,spacercarft,craft,offspring等。其中请特别注意－s结尾的单复数同形的名词，它们是考试的重点！3.不可数名词
不可数名词前一般不需要加定冠词，永远不能加不定冠词！例如下列用法均属错误：
the mathematics the banking a cloth an equipment
不可数名词作主语，谓语要用单数形式。如：water ** important.
但如果不可数名词前面被piece,drop,set等词修饰时，谓语应该与piece,drop,set等的单复数形式保持一致
例如：few drops of water are needed to s**e the flower.
下面是典型的不可数名词，是应该熟记的！air,smoke,steam,vapor,hydrogen,oxygen,nitrogen,water,oil,soup,juice,ink,rain,snow,ice,tea,coffee,wine,sunlight,sunshine,
lightning,thunder,weather,darkness,heat,light,electricity,energy,power,sugar,salt,rice,corn,powder,flour,sand,dust,dirt,
garbage,grass,hair,furniture,luggage,clothing,mail,equipment,food,meat,fruit,bread,toast,stone,iron,copper,chalk,**,
glass,wood,money,poetry,jewelry,machinery,weaponry,personnel,scenery,happiness,kindness,honesty,friendship,attention,wi
sdom,success,courage,br**ery,health,wealth,ignorance,trouble,ease,luck,laughter,love,peace,news,**rmation,knowledge,
intelligence,fun,pleasure,entertainment,enjoyment,recreation,relaxation,progress,room,work,homework,population,percent,
mathematics,econmics,stat**tics,meteorology,anthropology,architecture,physics,photography,ethics,politics,mechanics,
genetics,geology,geography,chem**try,philosophy,biology,h**tory,music,measles,mumps,diabetes,malaria,pediatrics,
obsterics
请特别注意其中以－s结尾的不可数名词，大家平时应该积累遇到的不可数名词
注意下列可数名词！poet poem essay news** machine weapon scene photograph photographer
英语中有许多名词既可作可数，又可作不可数。如:hair作“人或动物的毛”的时候是可数名词，作头发解释时是不可数名词。判断一个词是否可数，除了记忆以外，主要看题中该名词的修饰词来决定。如：much只能修饰不可数名词
4.单数形式和复数形式的词义不同的名词
英语中有些名词的复数形式的词义不同于单数形式，如：
air(空气)-air(气派)arm(手臂)-arms(武器)ash(灰)-ashes(骨灰；废墟)
authority(权利)-authorities(当局)cloth(织物)-clothes(衣服)content(含量)-contents(目录)
custom(习惯)-customs(海关；关税)damage(损害)-damages(赔偿金)force(力量)-forces(**部队)
glass(玻璃)-glasses(眼镜)good(利益)-goods(货物)green(绿色)-greens(青菜)
letter(字母)-letters(文学)manner(方式)-manners(举止，仪态)minute(分钟)-minutes(记录)
pain(痛苦)-pains(劳苦)papaer(纸)-**s(文件)quarter(1/4)-quarter(宿舍)
spectacle(光景)-spectacles(眼镜)spirit(精神)-spirits(烈性酒)time(时间)-times(时代)
water(水)-waters(水域)wood(木头)-woods(森林)work(工作)-works(工厂)
总结
1.单数名词不能单独存在，一般前面应该有限定词修饰。2.不定冠词a/an永远只能修饰单数可数名词。3.every和each永远只能修饰单数可数名词。但every+数词+复数名词是正确的，如：every ten years
4.序数词后面一般使用单数可数名词。5.anther永远只修饰单数可数名词
但another+数词/few+复数名词是正确的，如：another eight years;another few books
6.other通常修饰复数名词，也可修饰不可数名词。但the other+**/was 单数名词或any other+单数名词是正确的，如
we h**e two girls in th** team.one ** mary,the other ** alice.
henry smith ** taller than any other student in h** class.
7.下列词和短语只能修饰复数名词
these,those,many,various,several,numerous,diverse,few,a few,both,a(good/large/great)number of,numbers of,one of
8.大于1的词数只能修饰复数名词
牢记的结构：one/two/many+of+限定词+复数名词！9.只能修饰单数可数名词的词：
one,anther,a/an,th**,that,each,every,either,such a,many a
注意！many student以及many a student
10.只能修饰复数可数名词的词：
1的数字（two,six.),hundred,thousand,million,both,several,many,few,a few,these,those,a(good/large/great)number of
numbers of,the numberof,numbers of,numerous,various,diverse,a series of,a wide range of,a collevtion of
11.只修饰不可数名词的词：
much,little,a litter,a great deal of,a great amount of,a piece of,an article of
12.既可修饰不可数又能修饰可数的词：
all(of)a lot of some(of)lots of any(of)
plenty of most(of)half(of)a wealth of(a)part of
enough(of)the rest of other one third of such
no a variety of