Busman's holiday refers to a holiday that you spend doing the same kind of thing that you usually do for your job. 

“工作假日”指的是照常工作的休假日。

If you have a holiday, but spend it doing something similar to your usual work, you can refer to it as a busman's holiday . 

如果你在休假，但却做着和平日工作时差不多的事情，就可以称之为“工作假日”。