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

Sentence: 'a mouse and keyboard sitting on a wooden desk'. Replace the letter 'a' with 'n' in the sentence.
n mouse nnd keybonrd sitting on n wooden desk

Sentence: 'this is a tennis player getting ready to serve the ball'. Replace the letter 'h' with 'y' in the sentence.
tyis is a tennis player getting ready to serve tye ball

Sentence: 'a big giraffe reaches for food while two younger ones stand around'. Replace the letter 'e' with 'g' in the sentence.

a big giraffg rgachgs for food whilg two younggr ongs stand around