this is a letter改为复数句

this is a letter改为复数句 this is letter A.改为否定句 This is a book 改为复数句 This is a pear.改为复数句 this is a book改为复数形式 This is a dress.改为复数形式 this is a tree 改为复数句 Is this a bus （改为复数句 This is a bus.改为复数. this is a shirt改为复数句 this is a strawberry改为复数 This is a young tree.(改为复数) this is a watch(改为复数句) This is a knife 改为复数 This is a cat.(改为复数形式) this is a pen.改为复数句 This is a shirt .改为复数句 this is a pencil改为复数句