以“f”结尾的单词直接加“s”变复数的s所有单词

roofs, proof s, chiefs.

2)以s、x、sh、ch结尾的名词加es: glasses, boxes, brushes, matches.

3)以辅音字母加y结尾的名词，变y为i加es: cities, babies, enemies.4)以f或fe结尾的名词，多数变f为v加es: wives, knives.但有些词只加s: roofs, proof s, chiefs.

5)以o结尾的名词，有些加es: Negroes, heroes, tomatoes, potatoes.其它加s: radio s, zoos, pianos, photos.

6)不规则名词：foot→feet, goose→geese, tooth→teeth, child→children, man→me n, woman→women, sheep→sheep, deer→deer, mouse→mice.

7)某些外来词变复数：datum→data, medium→media, bacterium→bacteria, curriculum→curricula, criterion→criteria, phenomenon→phenomena. (um/on→a)analysis→analyses, basis→bases, crisis→crises, diagnosis→diagnoses.(is→es )

8)复合名词变复数：以不可数名词结尾的复合名词无复数形式，如：homework.

以man或woman为前缀的复合名词变复数，前后两个名词都变复数，如：manservant→menservants, woman student women students.

其它复合名词变复数：grownup→grownups, brotherinlaw→brothersinlaw, standby→standsby.参考资料：http://zhidao.baidu.com/question/11459346.html?si=3

belief

chief roof proof

roofs, proof s, chiefs.