2 Mexicans

A Border Patrol agent is on duty. He spots two Mexicans and runs them down. They show him their papers (he thinks they are phony).

He tells them, O.K. I have a test for you. I want you to use the words cheese and liver in a sentence.

So, the first guy says, I made a liver and cheese sandwich for lunch.

The agent says, That was good, you can go. What about you? he asks the second guy.

He says, Liver alone. Cheese mine.