问题描述：
1.把下列名词单数变成复数
him?this?her?watch?child?photo?diary?day?foot?book?dress?tooth?sheep?box?bike?thief?yo-yo?peach?sandwich?man?woman?paper?juice?water?milk?rice?tea?bus?wife?story?foot?potato?boy?policewoman?sheep?class?knife?leaf?tomato?tooth?strawberry?zoo?piano?car?cat?match?city?mango?brush?map?apple?