This is their school改为否定句

They do their homework after school 改为否定句 they will visit their grandpa this weekend 改为否定句 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 this is letter A.改为否定句 This is my father()改为否定句 This is my grandmorther.改为否定句 This is a watch.改为否定句.