It's a beautiful Spring day, and I am out for a walk in the woods. Suddenly, I come to a large mysterious red door, guarded by two large guards.
A sign on the door says:
==> "You are allowed through this door only if you KNOW whether or not it is locked. You may not try the door, but you may ask one guard one question."
A sign stands behind the guards. It says:
==> "One of these guards ALWAYS tells the truth. The other guard ALWAYS lies."

Is it possible for me to ask ONE guard ONE question, and find out whether or not the door is locked ?