名词单复数
1.一般情况，直接加-s，如：book-books, bag-bags, cat-cats, bed-beds
2.以s. x. sh. ch结尾，加-es，如：bus-buses, box-boxes, brush-brushes, watch-watches
3.以“辅音字母+y”结尾，变y为i, 再加-es，如：family-families, strawberry-strawberries
4.以“f或fe”结尾，变f或fe为v, 再加-es，如：knife-knives
5.不规则名词复数：
man-men, woman-women, policeman-policemen, policewoman-policewomen, mouse-mice
child-children, foot-feet, tooth-teeth, fish-fish, people-people, Chinese-Chinese, Japanese-Japanese
不可数名词的复数就是原型： paper, juice, water, milk, rice, tea