that's that (或 so that's that) 〈口〉[加强语气用](表示决定、结束争论、讲完故事、完成任务等时用语)就这样决定了；就是这样；再没有什么可说的 We will finish the task in three days, and that's that. 我们一定要在3天内完成任务，就是这样。 So that's that. We'll meet here tomorrow morning. 就这样定了，我们明天上午在这里相会。 It was a policy, and that was that. 那是政策，没有什么可多讲的。