Mary cheated secretly in the test, and never got caught.
1988 October 2, James Atlas, “DABBLING IN LOVE - NOT THE NICE KIND”, in The New York Times[1]:
Sometimes her prose hyperventilates ("Once, years ago, his and N.'s love for each other had glowed like phosphorescent fire on the surfaces of their bodies"), and she has a weakness for epiphanies ("There was a man, no longer young, though not yet old, who, traveling alone in northern Europe, began to feel that his soul was being drained slowly, almost secretly from him, drop by drop").