this is a box.变复数句___________?

this is a box.变复数句___________? this is knife in the box（变复数句 This is a box.改为复数形式 this is a box改为复数 英语~①This pen is in the pencil-box（变复数）①This pen is in the pencil-box（变复数）②Those red watches are Jim's（变单数）③She is a good girl（变感叹句）④Her friend goes to shanghai every month（变否定句,一般 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 marker怎么变复数句 This is a box and that is a knife （改为复数句） This box is small.改为,同义句.This box __ __. There is an apple in the box.变复数句 英语怎么变复数形式?如：This is a box.要说出怎么是这样变的？ This is a box and that is a knife.改为复数形式〔怎么变的〕 this.is pen变复数句 This is a[backpack]变否定句、对画框部分提问、变复数句RT What is this? It is a box.复数形式 This is an eraser That is aThis is an eraserThat is a plate变复数句