How often one hears children wishing they were grown up, and old people wishing they were young again. Each age has its pleasures and its pains, and the happiest is the one who enjoys what each age gives him without wasting his time in useless regrets. Childhood is a time when there are few responsibilities to make life difficult. If a child had good parents, he is fed, looked after and loved, whatever he may do. In addition, life is always presenting new things to the child things that have lost their interest for older people because they are too well known. A child finds pleasure in playing in the rain, or in the snow. His first visit to the seaside is a marvelous(非凡的) adventure. But a child has his pains., he is not so free to do as he wishes as he thinks older people are he is continually being told not to do things, or being punished for what he has done wrong. His life is therefore not perfectly happy. When the young man starts to earn his own loving, he becomes free from the discipline (纪律) of school and parents but at the same time he forced to accept responsibilities (责任). He can no longer expect others to pay for his food, his cloths, and his room, but has to work if he wants to live comfortably. If he spends most of his time playing ahout in the way that he used to as a child, he will go hungry. And if he breaks the laws of society as he used to break the laws of his parents, he may go to prison. If, however, he works hard, keeps out of trouble and has good health, he can have the real happiness of seeing himself make steady(稳定的) progress in his job and of building up for himself his own position in society. Old age has always been thought of as the worst age to be but it is not necessary for the old to be unhappy. With old age should come wisdom and the ability to help others with ad vice wisely given. The old can have the joy of seeing their children making progress in life they can watch their grandchildren growing up around them and, perhaps best of all, they can, if their life has been a useful one, feeling the happiness of having come through the bat tie of life safely and of having reached. a time when they can lie back and rest, leaving others to continue the fight. The title of the passage is______.