You guys are oblivious. That was just a printed copy from his computer, probably one that he photocopied for the rest of the class. Hence, he still has the questions in his computer. Just b/c he can't find his printed copy doesn't mean a thing, he probably will just think he had lost it and print out another. Teachers are lazy and usually won't change test questions just b/c they lost a copy somewhere, unless the test was identified (if his name/class/phone # were on that copy). If it was just a piece of paper with the questions, then don't worry about it. If it's identified, don't be surprised to see different questions/different version, but memorize the answers to your copy just in case. On a sidenote, good teachers usually keep different versions of their tests, but it depends on the teacher. This one sounds lazy, although only you know if he is or not (more details please).