会英语的进来~IS this your box?改为复数句是Are these your boxes?为什么要用Are呢

会英语的进来~IS this your box?改为复数句是Are these your boxes?为什么要用Are呢 is this your ruler? 改为复数句 Are these her erasers?改为单数句 is that your photo改为复数句 are these her borthers 改为单数句 Are these your friends.改为单复数 Is this your sister?(改为复数句） Those are Zhang jie is aunts.(改为 this your friend?(改为复数形式) 问题二Are these your books?(改为单数形式) ' 改为同义句:Is this your car?These pants are hers.Th These are boxes. (改为单数句） These pens are blue.(变否定句） Is that your photo?(变复数句） This is These are your sisters.改为否定句 These are your brothers改为否定句 Are these your rubbers?(改为同义句)