No one can fail to stand in awed ( 令人敬畏的 ) admiration of the great discoveries of history—Newton' s laws of motion; Kepler' s principles of planetary movement, Einstein' s general theory of relativity. Equally awe-inspiring are artistic creations in painting, theatre, music and literature, which have also been brought about by discovery through personal efforts.  What do these extraordinary achievements of well-known scientists and artists have to do with problem solving? A great scientific discovery or a great work of art is surely the result of problem-solving activity. The solution to a problem, we are told, often comes to thinkers in a “flash of insight (顿悟) ”， although they may have been turning the problem over in their minds for some time. As a particular form of problem solving, these creative acts are based on the broad knowledge gained in the past, whether this be of the public' sort known to science, or of the 'private' sort known to the artist. Many creative thinkers state that they have completely devoted themselves to the subject matter of the problem, often over fairly long periods of time. Indeed, it would be strange if they had not done this. Nothing in such statements supports the idea that there is anything very different about the problem solving that leads to discoveries of the great contributions to the society. The act of discovery, even in the relatively predictable (可以预见的) sense that it occurs in everyday learning, involves (涉及) a “sudden insight” which changes the problem situation into a solution situation. As we have seen, everyday discovery also requires that the learner have the knowledge of the rules gained in the past, which is involved in the solution. 52. Newton, Kepler and Einstein are mentioned in the first paragraph to_______. A. bring about the subject of the discussion B. explain that scientists are more creative C. show the difference between science and arts D. prove that arts require more personal efforts 53. While knowledge from the past plays an important role in their achievements, thinkers sometimes also depend on their______. A. artistic tastes                    B. sudden insight C. admiration of discoveries  D. scientific experiments 54. What does the underlined word “this” refer to? A. Great contributions to the society B.  Long-time study of the subject matter. C.  Various statements about problem solving. D. Complete devotion to artistic creation. 55. We may conclude from the passage that ______. A.it is more likely to make scientific and artistic discoveries in everyday learning. B. a sudden insight and knowledge from the past are required in making discoveries C. scientific discoveries or artistic creations are usually unpredictable in nature D. knowledge of the rules in the past is often developed in the changes of situation