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 seminar in an auditorium. Sentence 2:  A seminar in the auditorium.
A seminar on a beach in the water.

Sentence 1: A man in a red uniform makes a jump in a dirt bike race. Sentence 2: The man is competing against other racers.
The man is riding by himself.

Sentence 1: A rodeo rider is riding a bucking horse in an arena. Sentence 2: A man is riding a horse.

The man is riding a bull.