The didn't-do list is list of things you intended to do at the beginning of a month or a week, or even a day, but failed to get them done by the planned deadline. It is a to-do list that keeps a record of undone1 things.
未办事情列表指在每一个月、每周甚至天天开始的时候,列出一些计划完成的事情,可在计划的截止时间却发现事情都未完成。未办事情列表其实就是没按计划完成的待办事情列表。
这个didn't-do list其实就是在to-do list的基础上衍生出来的,to do表示计划要做,而过去式的didn't do则表示未完成。