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

Sentence: 'a young boy in a shopping cart looking at tooth brushes'. Replace the letter 'o' with 'r' in the sentence.
a yrung bry in a shrpping cart lrrking at trrth brushes

Sentence: 'a no parking sign next to a car riding down a street'. Replace the letter 'g' with 'l' in the sentence.
a no parkinl siln next to a car ridinl down a street

Sentence: 'a baseball player waits for action on the field'. Replace the letter 'l' with 'x' in the sentence.

a basebaxx pxayer waits for action on the fiexd