【答案解析】{{B}} All Work No Play Makes Jack a Dull Boy{{/B}} Despite the fact that all human great achievements are based on his work, yet work itself is not and should not be all his live. To be really happy, one has not only to work in an effort to make his living, but also to play in order to make his work more efficient. Scientific studies have been made of the real nature of what is termed more definitely: recreation, of which play is the equivalent in this context. It is revealed that recreation is not so much needed in our lives for pleasure as for a change of atmosphere or a diversion of effort. One cannot be the best of his ability either in mental or in muscular effort provided that his effort is not diverted constantly. It is well known that a physical laborer having worked exhaustedly has to get relaxation for a recovery. Likewise, for mental workers like students, teachers or other professionals relaxation in one form or another is vital if they have strained their minds. Successful scientists are those who know quite well the fact that work is to alternate with play. For example, the noted chemist and inventor Alfred Nobel cultivated a keen fondness for literature. It is repeatedly noted that on the campus some students, either for fear that they lose too much time or for the purpose that they are well ahead of others, spare no time or energy for recreation, but contrary to their intentions, it turns out, as an old saying goes, that haste makes no speed--such an attempt only aggravates the strain of the mental effort and thus prevents them from achieving greater success. One of the consequences of all work without play is the inevitable decline in health and physique. On the contrary, rational arrangement of work alternating with play brings about a process of recuperation and repair.