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 motorcycle sitting on the side of the road by grass'. Replace the letter 'r' with 't' in the sentence.
answer:
a mototcycle sitting on the side of the toad by gtass


question:
Sentence: 'a man walking in the rain while holding an umbrella'. Replace the letter 'b' with 'z' in the sentence.
answer:

a man walking in the rain while holding an umzrella