You can refer to a task or a job as a treadmill when you have to keep doing it although it is unpleasant and exhausting.
例句
Mr Stocks can expect a gruelling week on the publicity treadmill.斯托克斯先生可以预见下一周会被枯燥繁重的宣传工作搞得焦头烂额。
N-COUNT
踏车;跑步机
A treadmill is a piece of equipment, for example an exercise machine, consisting of a wheel with steps around its edge or a continuous moving belt. The weight of a person or animal walking on it causes the wheel or belt to turn.