阅读下面短文，把A～D四个句子填入文中空缺处（1~4），使短文内容完整正确，然后完成第5题。
We often hear that children wish they were grown-ups，and that old people wish they were young． 1 The happiest people enjoy what each age gives them without wasting their time in useless regrets．
Childhood（童年）is a time when there are few duties．A child is fed，looked after and loved by all grown-ups like parents or grandparents．2 However，for older people they often lose their interest in those things．
On the other hand（另一方面），a child may also have some pains with him．3 He is often told not to do something．He will certainly be shouted at for doing something wrong．
When a child grows up，he can no longer expect others to pay for his food，clothes，room and many other things． 4 If he still spends most of his time playing as he used to in childhood，he will go hungry．If，however，he works hard and has no trouble，he can build up his own position in society with great happiness．
A．What's more，life is always giving new things to him．
B．And he has to work if he wants to live comfortably．
C．He is not so free to do what he wishes to do．
D．Each age has its own pleasures and its own pains．
5．What is the best title of the passage?
A．Childhood Is a Happy Time B．No Pains at Any Age
C．Happy Position in Society D．Enjoy Your Whole Life