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.

Sentence 1: A dog running on the sand. Sentence 2: a dog is running on sand
a dog is playing with sheep in a grass field

Sentence 1: Two men carrying briefcases look across the street in a city. Sentence 2: There are two men looking across the street.
Two men carrying briefcases knock on the door of the rural farm house.

Sentence 1: An old man sits. Sentence 2: A man is sitting.

An old man running in a park.