Ball这单词是我们学英语时最早学到的词汇。它多指“球，舞会”。但由ball构成的短语也应该会使用。下面学习五个常见短语。
1.当我们表示“下一步就看你的了”时，我们就可以用the ball is in your/sb's court。例如，The ball is in your/sb's court，it is your responsibility to take action next.下一步就看你的了。下一步采取行动是你的责任。They've offered me the job, so the ball's in my court now.他们已答应把那份工作给我，下一步就看我怎么办了。
2.短语a ball of fire不是“火球”，而是一个指“精力充沛热情洋溢的人；生龙活虎的人；朝气蓬勃的人”。例如：
I hope John will join us, he is a ball of fire.我希望约翰能加入我们，他是个精力旺盛的人。Eric is not a good student, but on the basketball court he is a ball of fire.埃里克不是好学生，但在篮球场上他很活跃。
3.当我们想表达“开始某事；继续某事”时，我们也可以用get/set/start/keep the ball rolling。例如：
Let's keep the ball rolling on this project.我们应该保证这个项目的进度。My host had very little to talk about, and it was very difficult to keep the ball rolling.我的主人没有什么话可谈了，因此谈话很难继续下去。
I’ll start the ball rolling by telling you a few ideas I already have.我先来开个头，把我已经想到的几个想法给大家谈一谈。OK, everyone. Let's get the ball rolling. Come and sit down and we'll start the meeting.好了各位，我们开始吧。来，请坐，会议要开始了。
4.have a ball可以表示“狂欢；玩得痛快”。例如， We intend to have a ball at the amusement park today.我们打算今天到游乐场玩个痛快。Outside the boys were sitting on the ground and, judging by the gales of laughter, they were having a ball.男孩子们在外面席地而坐，从他们发出的阵阵笑声来看，他们玩得很开心。
5.短语(be) on the ball则表示“敏锐；机警”。例如，The new publicity manager is really on the ball.新任宣传部经理的确精明干练。You can trust him; he's got a lot on the ball.你可以相信他，他很有本领。
