Is that his backpack the lost and found case?”处填什么?on in at of?

is that your friend 改为复数句 is this his backpack作否定回答 Is that his backpack the lost and found case?”处填什么?on in at of? That is a backpack in English .(划线提问)提问backpack Is this his backpack -no it is that green backpack to him最后为什么要加him求原因是No,it is not.That green backpack (belongs) to him. It is his backpack改否定句 his pen is backpack 修改病句 This is his backpack.改成否定句 中文意思：this backpack is his. Is this his backpack?肯定回答 Is this his backpack （做出肯定的简略回答） Is that her nice watch（改为肯定的陈述句） is that your backpack改为复数 Is that your backpack?的中文意思 That is her backpack 改成否定句 That is you backpack 改为复数 his watch is in his backpack改为否定句 Is his backpack on his desk?否定和肯定回答、 Whose is that backpack?(改为同义句) _______ does that backpack ______ ________? not、 is、 his、 backpack、 it连词成句