It is pen复数.和this is an eraser复数.还有he isboy复数

It is pen复数.和this is an eraser复数.还有he isboy复数 This is pen变复数 This is his pen.复数形式 this.is pen变复数句 this is a pen.改为复数句 This is a pen.(改为复数形式) is this( )Japanese pen?yes,it is It is my pen.(改为复数形式) This开头和 It is开头用法的区别例；This si a pen和It is a pen 英语 改复数句This is a pen.Is this your backpack?It's a black bag Is This your pen?No ,it's__________ is this a pen?No it i(). this is () pen,but it's ()broken pen this is( )my pen.it's( )pen.( )里填空 this is pen,it 's englishthis is pen,it 's english pen What is this 是This is a pen.还是.It is a pen?为什么? this is my pen pal改成复数形式 This is a pen 变为复数如题