Question: To whom did Chopin reveal in letters which parts of his work were about the singing student he was infatuated with?
Sentence: In letters to Woyciechowski, he indicated which of his works, and even which of their passages, were influenced by his fascination with her; his letter of 15 May 1830 revealed that the slow movement (Larghetto) of his Piano Concerto No. 1 (in E minor) was secretly dedicated to her – "It should be like dreaming in beautiful springtime – by moonlight."
Answer in sentence: no