This is a tomato变复数形式是?

This is a tomato变复数形式是? This is a red tomato .(变复数） This is a knife.怎样变复数. this is a new car.变复数 This is a marker.（变复数） this is a piano怎么变复数 is this your tomato?（改为复数形式） This is pen变复数 is this that 变复数怎么变 This is a photo of my family.变复数 Is this a pen?（变复数句） This is a pen变为复数句,怎么变 This is a horse.变该句为复数形式 this is a box.变复数句___________? this is a marker怎么变复数句 this is a bix.变成复数的句子怎么变 句型转换 This is a red tomato（改为复数句） Those English books are good（改为同义句） there is a tomato here改为复数句