sweep是扫除的意思，而sweep the floor则是扫地的意思，区别可以从以下例子看出：

Today is my clean up day, there are so many area that need to be sweeped, of course I will sweep the floor. That is main job. 今天是我的大扫除日，要扫的地方太多了，我当然要扫地了。这是主要的工作。