Two good friends, Sam and Jason, met with a car accident on their way home one snowy night. The next morning, Sam woke up blind. His legs were broken. The doctor, Mr Lee, was standing by his bed, looking at him worriedly. When he saw Sam awake, he asked, "How are you feeling, Sam?" Sam smiled and said, "Not bad, Doctor. Thank you very much for doing the special operation ." Mr Lee was moved by Sam. When he was leaving, Sam said, "Please don't tell Jason about it." "Well...Well...OK," Mr Lee replied. Months later when Jason's wounds healed , Sam was still very sick. He couldn't see or walk. He could do nothing but stay in his wheelchair all day long. At first, Jason stayed with him for a few days. But days later, Jason thought it boring to spend time with a disabled man like Sam. So he went to see Sam less and less. He made new friends. From then on, he didn't go to visit Sam any more. Sam didn't have any family or friends except Jason. He felt very sad. Things went from bad to worse. Sam died a year later. When Jason came, Mr Lee gave him a letter from Sam. In the letter Sam said, "Dear Jason, I am disabled. But I want you to be a healthy man. So I gave my eyes to you so that you can enjoy life as a healthy man. Now you have new friends. I'm glad to see that you are as healthy and happy as usual. I'm glad you live a happy life. You are always my best friend... Sam". When he finished reading the letter, Mr Lee said, "I have promised that I will keep this a secret until Sam is gone. Now you know it." Jason stood there like a stone. Tears ran down his face. The car accident happened   _  .
only to Sam on a cold evening the next morning on the way to work