翻译以下段落 To realize the value of one year, ask the student who has failed to grade. To realize the value of one month, ask the mother who has given birth to a premature baby. To realize the value of one week, ask the editor of a weekly newspaper. To realize the value of one hour, ask two lovers who are waiting to meet. To realize the value of one minute, ask the traveler who has just missed his train. To realize the value of one second, ask the motorist who has just avoided an accident. To realize the value of one millisecond, ask the athlete who has won a silver medal in the Olympics. Treasure every moment that you have! And treasure it more because you have shared it with someone special, special enough to spend your time with. And remember that time waits for no one. Yesterday is history. Tomorrow is a mystery. Today is a gift. That's why it's called the present.