1、单词单数变复数规则1)单数名词加 s: students, apples, bags, trees, books, brothers.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, to
2、matoes, potatoes.其它加 s: radio s, zoos, pianos, photos.6)不规则名词：footfeet, goosegeese, toothteeth, childchildren, manme n, womanwomen, sheepsheep, deerdeer, mousemice.7)某些外来词变复数：datumdata, mediummedia, bacteriumbacteria, curriculumcurricula, criterioncriteria, phenomenonphenomena. (um/ona) analysisanal
3、yses, basis bases, crisiscrises, diagnosisdiagnoses.( 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：manservantmenservants, woman student women students.其它复合名词变复数：grown upgrown ups, brotherinlawbrothers inlaw, standbystands by.9)复合形容词做定语时，其中的名词保持单数：a six-year old boy，a two hundred page book
