question: To whom did Chopin write a letter on 21 February 1842 about his agonizing pain ?
answer: Grzymała
turker_answer: Chopin wrote a letter to Grzymała on 21 February 1842 about his agonizing pain .
rule-based: Chopin wrote a letter on 21 February 1842 about his agonizing pain to Grzymała .