instruction:
In this task, you need to replace a letter in the sentence with another given letter.
question:
Sentence: 'a man is somewhat hard to be seen in the wave, on his board'. Replace the letter 's' with 'b' in the sentence.
answer:
a man ib bomewhat hard to be been in the wave, on hib board

question:
Sentence: 'a woman walks by with a large suitcase and a polka dot umbrella'. Replace the letter 'e' with 'n' in the sentence.
answer:
a woman walks by with a largn suitcasn and a polka dot umbrnlla

question:
Sentence: 'a person that is sitting under an umbrella'. Replace the letter 'a' with 'l' in the sentence.
answer:
l person thlt is sitting under ln umbrelll