Definition
To progress more slowly than planned or expected, resulting in a failure to meet deadlines or targets.
落后于预定时间；落后计划
Due to supply chain issues, our production has fallen behind schedule.
由于供应链问题，我们的生产进度已经落后了。
If we don't speed up, this project will fall behind schedule.
如果我们不加快速度，这个项目将会进度落后。
The software development has fallen behind schedule due to unexpected technical issues.
由于意外的技术问题，软件开发进度已经落后了。