is that your backpack改为复数

can you tell me?whose backpack is that?合并成一句我的答案can you tell me whose that backpack is我做的答案是错的,我认为宾语从句的从句应该是陈述句子才用的that backpack is 正确答案是can you tell me whose backpac Is that your computer? that is your pen. Is that ( ) your sister is that your friend? is that your desk? Is that your that is your bilk is------------- Is that your pencil是什么意思 Is that your sister?,回答 I hope that is your That is your pencil,__ IS THAT YOUR BYOTHERS是什么意思 Grrr!Is that your coat? Is that your final answer?; ) Is that your love.Not that ID card your is Is that your estate Yes,it is