名词复数规则
1.一般情况下，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
写出下列各词的复数
I _________him _________this ___________her ______
watch _______child _______photo ________diary ______
day________ foot________ book_______ dress ________
tooth_______ sheep ______box_______ strawberry _____
thief _______yo-yo ______ peach______ sandwich ______
man______ woman_______ paper_______ juice___________
water________ milk________ rice__________ tea__________