Answer :
A counterexample proves something wrong. To disprove "When it rains, it pours," you could give an example of a time when it rains and does not pour. What if it only rains a little? What if it rains frogs? How are you supposed to "pour" frogs? I dunno. This is sort of an open-ended question. I'd go with "It drizzles, but does not pour."
