instruction:
In this task, you need to replace a letter in the sentence with another given letter.
question:
Sentence: 'a blue and white train is coming down some tracks'. Replace the letter 'b' with 'u' in the sentence.
answer:
a ulue and white train is coming down some tracks

question:
Sentence: 'a cook sanding between two women inside of a kitchen'. Replace the letter 'n' with 'y' in the sentence.
answer:
a cook saydiyg betweey two womey iyside of a kitchey

question:
Sentence: 'the boy is standing in a large pasture'. Replace the letter 'g' with 'k' in the sentence.
answer:
the boy is standink in a larke pasture