This is his backpack.改成否定句

This is his backpack.改成否定句 Is this your backpack?改成否定句怎么改 this is his ring改成否定句 That is her backpack 改成否定句 It is his backpack改否定句 is that your friend 改为复数句 is this his backpack作否定回答 his watch is in his backpack改为否定句 Is this his sharpener?改成肯定句 还有That is her ruler改成否定句! This is ablue backpack.(改错为否定句)This a blue backpack. This is my backpack.改成复数形式 this is my ruler改成否定句 This is a pagoda.改成否定句