单项选择题

People who question or even look down on the study of the past and its works usually assume that the past is entirely different from the present, and that hence we can learn nothing worthwhile from the past. But it is not true that the past is entirely different from the present. We can learn much of value from its similarity and its difference. A tremendous change in the conditions of human life and in our knowledge and control of the natural world has taken place since ancient times. The ancients could not, however, see in advance our contemporary technical and social environment, and hence have no advice to offer us about the particular problems facing us. But, although social and economic arrangements vary with time and place, man still remains man. We and the ancients share a common human nature and hence certain common human experiences and problems. The poets bear witness that ancient man, too, saw the sun rise and set, felt the wind on his cheek, was possessed by love and desire, experienced joy and excitement as well as frustration and disappointment, and knew good and evil. The ancient poets speak across the centuries to us, sometimes more directly and vividly than our contemporary writers. And the ancient prophets and philosophers, in dealing with the basic problems of men living together in society, still have something to say to us. We also learn from the past by considering the respects in which it differs from the present. We can discover where we are today and what we have become by knowing what the people of the past did and thought. And part of the past—our personal past and that of the race—always lives in us. In the first line of the last paragraph, the sentence "We can discover where we are today..." means______.