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

Q: Sentence: 'a mobile phone and a set of keys on a key chain'. Replace the letter 's' with 'j' in the sentence.

A: a mobile phone and a jet of keyj on a key chain
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Q: Sentence: 'a baseball player is throwing a ball across the dirt field'. Replace the letter 'a' with 't' in the sentence.

A: t btsebtll pltyer is throwing t btll tcross the dirt field
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Q: Sentence: 'a passenger train that is driving on some tracks'. Replace the letter 't' with 'q' in the sentence.

A:
a passenger qrain qhaq is driving on some qracks
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