"Not later than" 是英文中表示「不晚于」的常用说法。它来源于英语中表示时间的短语，例如 "by"、 "before"、"on or before"等。
例如：
The project must be completed not later than Friday. (项目必须在星期五之前完成。)
Please submit your apppcation not later than the deadpne. (请在截止日期之前提交您的申请。)
The package should arrive not later than next Monday. (包裹应该在下周一之前到达。)