Have you ever dreamed about sending a letter to yourself or your friends in the future? While express mail  is a fast way to send your letters, there is another type of mail appearing in China as a new business--future mail. "The letter should be sent next Mother's Day and not a day earlier!" Lin Xiaofan, a college student in Shanghai, tells one of the companies offering the service. Lin Xiaofan wrote the letter to her mother nearly a year earlier to express her love to her mother for next Mother's Day. "Offering this service makes people slow down and lets them understand the meaning of 'time' in another way," said Zheng Zhimin, manager at a "future mail" company. Zheng thinks "future mail" letters help remind us of care, friendship and love. While "future mail" is becoming more and more popular, some people are wondering what will happen if the postal address changes or if the company goes broken before the letters arrive. Zheng said customers are glad to sign a contract  to make sure that they can be _ if their letters are lost or damaged. Most of the customers are college students and young white-collar  workers. Psychologists   said that young Chinese might have a new way to express their feelings through this service. Most people put their hopes and wishes in the letter so that they can experience the connection  between the past and the present when they receive the letter. The "future mail" service is popular among   _  .
junior students college students young children blue-collar workers