Mark sat down and crossed his arms. Having a baby sister is a big responsibility(责任)，” Grandpa said. "Not really.She cries,and plays." Grandpa smiled,"That's not what I mean.I mean it's hard for you to share your parents with your little sister since you used to be the only child at home." Mark looked at him,"I don't see why she's so special. What about me?” 导航页导航页 Mark sat down and crossed his arms. “Having a baby sister is a big responsibility (责任),” Grandpa said. “Not really. She cries, and plays.” Grandpa smiled, “That’s not what I mean. I mean it’s hard for you to share your parents with your little sister since you used to be the only child at home.” Mark looked at him, “I don’t see why she’s so special. What about me?