A duck walks into a bar......
 
 
 
 

A duck walks into a bar and says "Do you have duck food here?"
The bartender says "No" and the duck leaves.

The duck comes back the next day and says "Do you have duck food?"
The bartender says "No."

The duck comes back the next day and says "Do you have any duck
food?"  The bartender says "I already told you 'No' twice!  If you
come back and ask me again, I'm going to nail your feet to the floor!"

The duck comes back the next day and says "Do you have any nails?"
The bartender says "No."

"Do you have any duck food?"