your sister had heart disease. You wanted to give her your heart. You wrote a letter for your sister when she wakes up after the surgery: "Dear sister, you are probably reading this letter after waking up and I am no longer in this world, I would like to tell you to take care of my heart and my pet, I wish you health and happiness!" , and you gave the letter in an envelope to your parents to give to your sister after she woke up. After surgery. The doctor left the operating room, approached the parents and said that the transplant was successful and your sister should wake up soon.