In this task, you're given a pair of sentences, sentence 1 and sentence 2, that neither agree with nor contradict each other. Your job is to alter sentence 2 so that the pair clearly 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 boy, wearing a gray shirt and black pants, is bowling with a black bowling ball with only two pins left to knock down. Sentence 2: A boy is bowling with his friends.
A boy bowls with a black bowling ball

Sentence 1: A woman in a black dress is leaning against a wall, smoking a cigarette. Sentence 2: The woman is sad
A woman is smoking

Sentence 1: A man is balancing a metal ball on his arm. Sentence 2: A man is balancing a metal ball as a demonstration to his students.

A man is balancing a metal ball.