1）一些特殊变化
| 单数 | 复数 |
| woman | women |
| man | men |
| child | children |
| tooth | teeth |
| foot | feet |
| person | people |
| leaf | leaves |
| half | halves |
| knife | knives |
| wife | wives |
| life | lives |
| loaf | loaves |
| potato | potatoes |
| cactus | cacti |
| focus | foci |
| fungus | fungi |
| nucleus | nuclei |
| syllabus | syllabi/syllabuses |
| analysis | analyses |
| diagnosis | diagnoses |
| oasis | oases |
| thesis | theses |
| crisis | crises |
| phenomenon | phenomena |
| criterion | criteria |
| datum | data |
注意：由一个词加 man 或 woman构成的合成词，其复数形式也是 -men 和-women，如an Englishman，two Englishmen。但German不是合成词，故复数形式为Germans；Bowman是姓，其复数是the Bowmans。
2） 2）单复同形，如deer，sheep，fish，Chinese，Japanese 等。但除人民币的元、角、分外，美元、英镑、法郎等都有复数形式。如：a dollar, two dollars; a meter, two meters。
| 单数 | 复数 |
| sheep | sheep |
| fish | fish |
| species | species |
| aircraft | aircraft |
3）集体名词，以单数形式出现，但实为复数。例如：
people police cattle 等本身就是复数，不能说 a people，a police，a cattle，但可以说a person，a policeman，a head of cattle, the English，the British，the French，the Chinese，the Japanese，the Swiss 等名词，表示国民总称时，作复数用
如The Chinese are industries and brave. 中国人民是勤劳勇敢的。
4）以s结尾，仍为单数的名词，如：
a. maths，politics，physics等学科名词，一般是不可数名词，为单数。
b. news 为不可数名词。
c. the United States，the United Nations 应视为单数。
The United Nations was organized in 1945. 联合国是1945年组建起来的。
news The news is on at 6.30 p.m.
athletics Athletics is good for young people.
linguistics Linguistics is the study of language.
darts Darts is a popular game in England.
billiards Billiards is played all over the world.
d. 以复数形式出现的书名，剧名，报纸，杂志名，也可视为单数。例如：
"The Arabian Nights" is a very interesting story-book. 《一千零一夜》是一本非常有趣的故事书。
5） 5）表示由两部分构成的东西，如：glasses （眼镜） trousers, clothes等，若表达具体数目，要借助数量词 pair（对，双）; suit（套）; a pair of glasses; two pairs of trousers等。
trousers My trousers are too tight.
jeans Her jeans are black.
glasses Those glasses are his.
6）另外还有一些名词，其复数形式有时可表示特别意思，如：goods 货物，waters 水域，fishes（各种）鱼。
