TASK DEFINITION: In this task, you're given a pair of sentences, sentence 1 and sentence 2, that agree with each other. Your job is to alter sentence 2 so that the pair contradict each other. Generated sentences must be short, with less than 15 words. New information can be introduced. Avoid using pronouns to confuse the subject of the sentence.
PROBLEM: Sentence 1: A person wearing a hat and baggy pants is skateboarding on cement. Sentence 2: A human rides a skateboard.

SOLUTION: An old man falls off a skateboard.

PROBLEM: Sentence 1: A family, grandparents, parents, and children, are sitting in front of a fireplace and a christmas tree opening presents. Sentence 2: A family, grandparents, parents, and children, are sitting

SOLUTION: A family, grandparents, parents, and children, are not sitting

PROBLEM: Sentence 1: The bike is upside down on the ground and being looked at by a man in a blue shirt and another man in a red shirt. Sentence 2: Two men are observing a bicycle laying on the ground.

SOLUTION:
The two men are planning a trip to the ballet.