An American is visiting his friends in Paris... ...and he is having trouble understanding some of the French idioms. ""Specifically,"" he says, ""the French expression *sang froid*. I know it literally means 'cold blood', but when would you use it?"" The first Frenchman nods and says, ""It is when you walk into your bedroom and see your friend making love with your wife. If you simply close the door and leave, then you have *sang froid*."" ""*Non, non, non*,"" the second Frenchman exclaims. ""It is, if you see your friend making love and you say, 'Pardon the intrusion, continue please, then you have *sang froid*."" ""*C'est formidable, mais...*"" the third Frenchman begins, ""The real meaning, it is this: If you see your friend making love to your woman, and you say, 'Pardon the intrusion, continue please,' and he **does**, then **he** has *sang froid*.""