将单词装换,单数的装换复数,将复数装换单数!

wife,wives
woman doctor,women doctors
children,child
father-in-law,fathers-in-law
wolf,wolves
knife,knives
desk,desks
chinese,chinese
glass,glasses
strawberry,strawberries
boy,boys
teeth,tooth
watch,watches
tomato,tomatoes
photo,photos