For people to best learn how to use an interactive product, they should be able to examine and experiment without fear of commitment or causing irreparable harm. The Undo function and Cancel button on each dialog box supports this function well.

• 为了更好地学习如何使用一个交互式的产品，人们应该能够观察和实验，而不必害怕承担后果或者是造成不可修复的破坏，每个对话框中的取消按钮和撤销功能很好地支持了这种功能。