Is that his ball改为复数并作肯定回答

Is that his ball改为复数并作肯定回答 That is his baseball.改为复数句 My tennis ball is (under the bed) .对括号部分提问 That is a soccer ball(改为复数） that is his brother 改为复数句 is that his key (改为复数形式) that is his pencil改为复数句 that is his sister改为复数形式 That is his friend.改为复数句 That book is his?改为复数形式 is that his pen?改为复数 That apple is his.(改为复数) his ball is under the table改为复数句怎么改 That is his book.怎么改为复数句 This is his ruler(改为复数句) That is my key(改为复数句) These are his brother whose is that ball 改为同义句 This is his sister and that is his son.怎么改为复数形式 This is my brother.改为一般疑问句 that is his photo.改为复数形式 This is his sister and that,s his son.怎么改为复数形式