In this task, you are given a premise sentence. Your task is to write a new sentence by substituting the subject and object (i.e., the input's subject should be output's object and vice versa.). The generated sentence must be fluent and shouldn't change the voice (i.e., passive or active) of the input.

The senator behind the students stopped the judge .
The judge stopped the senator .

The actors introduced the authors .
The authors introduced the actors .

The students recognized the professor that avoided the doctors .

The professor recognized the students .