In this task, you need to replace a letter in the sentence with another given letter.

Sentence: 'a cat sits on the floor next to a purse'. Replace the letter 'a' with 'b' in the sentence.
b cbt sits on the floor next to b purse

Sentence: 'someone playing frisbee with a dog in the middle of a court'. Replace the letter 'd' with 'r' in the sentence.
someone playing frisbee with a rog in the mirrle of a court

Sentence: 'a man is walking along a beach and carrying a surfboard'. Replace the letter 'g' with 'q' in the sentence.
a man is walkinq alonq a beach and carryinq a surfboard