TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a zebra standing by a pile of large rocks'. Replace the letter 'i' with 'x' in the sentence.

SOLUTION: a zebra standxng by a pxle of large rocks

PROBLEM: Sentence: 'three colorful knit bear toys with button eyes'. Replace the letter 'r' with 'z' in the sentence.

SOLUTION: thzee colozful knit beaz toys with button eyes

PROBLEM: Sentence: 'there are three whine glasses and four bottles of whine'. Replace the letter 'w' with 'b' in the sentence.

SOLUTION:
there are three bhine glasses and four bottles of bhine