play ball 合作，让步并互相帮忙

　　You play ball with me and I'll play ball with you next time.

　　你跟我合作，下次我一定跟你合作。

　　We have to play ball with Jack to finish this task.

　　为了完成任务，我们只能和Jack合作。

　　疯狂练习吧！