①Do they have a ping-pong bat?---Yes,【 I do.】
②【Does 】Mike have a baseball and baseball bat?---Yes,【he does.】
不明白的再问哟,请及时采纳,多谢!①Do they have a ping-pong bat?---Yes,【 I do. 】为什么是I①Do they have a ping-pong bat?---Yes,【 they do. 】主语是they， 所以是 Yes, they do. 请原谅我的 carelessness.