I found this good advice in the comments at ScienceBlog.
A Jesuit and a Franciscan sit in the train, both praying the breviary. Suddenly the Jesuit pulls out a silver cigarette box, and starts smoking. Asks the Franciscan indignantly: “How dare you smoke while praying?” The Jesuit responds: “Oh, I have asked Rome and got permission”. The Franciscan is interested and also writes to the Holy See.
Two weeks later the two priests meet again and the Franciscan complains: “You finely made a fool out of me, of course Rome denied to give permission”. Asks the Jesuit: “And how did you actually word your question?”
The Franciscan: “I asked whether it is allowed to smoke while praying…” “Wrong from the start”, interrupts the Jesuit, “you should have asked if it is allowed to pray while smoking….”