This cat is purple改为否定句

This cat is purple改为否定句 Is that pencil new?改为肯定句 look at this cat.(改为否定句） I want the I think it is a cat 改为否定句 Her aunt is playing with a cat.(改为否定句) this is a black cat.改否定句怎么改 is this a cat in Englisn作否定句 This is a clock改为否定句 This is my ruler (改为否定句) This is my room 改为否定句 this is my friend.(改为否定句) This is his pencil.(改为否定句) this is my brother 改为否定句