Plurals复数转换规则汇总

As a general rule, the plural is formed by adding "-s" to the singular form of nouns. 最常见的是在单数形式后面直接加 "-s" (来源：www.EnglishCN.com)

• shoe –> shoes
• book –> books
• river –> rivers

Nouns ending in "s" or "s" will generally take the ending "-es"  : 以"s"结尾的通常加"-es"

• bus –> buses
• kiss –> kisses

Words ending in "y" will generally take the ending "-ies" in place of the "y": 以"y"结尾的通常转换为"-ies"

• party –> parties
• supply –> supplies

Certain words have very irregular forms in the plural: 下面是精选的不规则复数形式，需要记住。

• one man –> two men
• one woman –> two women
• one person –> two people
• one foot –> two feet
• one mouse –> two mice
• one goose –> two geese
• one tooth –> two teeth
• one wife –> two wives
• one child –> two children
• one knife –> two knives
• one thief –> two thieves
• one dwarf –> two dwarves (ou: dwarfs)
• one potato –> two potatoes
• one leaf –> two leaves
• one life –> two lives
• one loaf –> two loaves
• one half –> two halves

A small set of words do not change form in the plural:下列词单复数同形

• one moose –> two moose
• one sheep –> two sheep
• one aircraft –> two aircraft

Words of Greek or Latin origin which have retained their original endings will generally take the plural form associated with the language they are drawn from: 来源于希腊语或者拉丁语的单词复数形式比较特殊，很容易拼错，请记住下面这些单词

• one alumnus –> two alumni
• one syllabus –> two syllabi
• one alumna –> two alumnae
• one alga –> many algae
• one criterion –> many criteria
• one forum –> many fora (or: forums)
• one thesis –> two theses
• one hypothesis –> two hypotheses
• one phenomenon –> two phenomena
• one cactus –> two cacti (or: cactuses)
• one diagnosis –> two diagnoses
• one oasis –> two oases
• one analysis –> two analyses

A few nouns are invariable or collective, always indicating a plural meaning下列名词属于集合名词只有复数含义:

• She gave me some information.
• Michelle has a lot of clothes.