where is my backpack 变复数

where is my backpack 变复数 改错here is nice backpack This is my book（变复数句） Where is my backpack?下半句是什么? This is my backpack.改成复数形式 Is this your backpack?变复数要怎么变啊! it is my watch变复数形式 the backpack is under the table.就画线部分提问 where's my backpack? where is backpack My dictionary is in the backpack.变一般疑问句 This is a[backpack]变否定句、对画框部分提问、变复数句 It is my backpack _your backpack this is my backpack复数,they are my aunts单数,those are my CDs划线