After the age of sixteen, as has been discovered, the number of our brain cells begins to decrease a

51. A    52. C    53. C    54. B
【解析】
这是一篇议论文。本篇文章主要说明了人类的大脑在20岁左右于巅峰，在以后的成就多数是因为需要丰富的经验。除了头脑敏锐经验丰富外，智慧也非常重要，因为智慧为人们提供了正确的努力方向。人们要用智慧来决定做什么才是最好的。
【51题详解】
细节理解题。根据文章第一段“when it has collected enough information to be able to use the vast number of cells freely in the most effective way. Pure mathematics is one of the fields in which this happens，and we know that Albert Einstein made all his world-shaking discoveries between the age of about 20 and 25”人类大脑在20世纪初达到了最高点，那时它已经收集了足够的信息，能够使用大量的细胞纯粹的数学是其中的一个领域，我们知道阿尔伯特•爱因斯坦在20到25岁之间做出了他所有的惊天动地的发现。可知爱因斯坦的伟大发现主要是由于 头脑敏锐。故选A项。
【52题详解】
推理判断题。根据文章第二段“But in certain other types of activity (of which being an author is perhaps one)，experience is more important than sharpness of brain，and there one usually finds that a person reaches his or her peak much later in life”但是在某些其他类型的活动中（作为一个作家可能是其中之一），经验比大脑的敏锐性更重要，人们通常会发现一个人在晚年生活中达到了顶峰。可知有些人在晚年取得成功是因为他们的工作往往需要很多经验。故选C项。
【53题详解】
推理判断题。根据文章第三段“Wisdom does not always come with age — there are plenty of foolish middle-aged people about — but the average person tends to learn wisdom as he gets older, usually by making painful or embarrassing mistakes. Learning to be wise is basically learning what is not possible and what is possible but so difficult that it is not worth all the trouble one has to go through to get there. Mostly, it is learning about human nature; how real people behave and react, as against how one would like them to behave and react. ” 智慧并不总是随着年龄的增长而增长——有很多愚蠢的中年人——但普通人往往随着年龄的增长而学习智慧，通常是通过犯痛苦或尴尬的错误。学习做一个明智的人基本上就是学习什么是不可能的，学习很可能但又很困难的东西以至于不值得一个人为了达到目标而付出所有的努力。主要是了解人性;真实的人的行为和反应，以及人们希望他们的行为和反应。由此判断出，智慧的重要性在于 它提供了正确的努力方向。故选C项
【54题详解】
推理判断题。根据文章第三段“ Learning to be wise is basically learning what is not possible and what is possible but so difficult that it is not worth all the trouble one has to go through to get there. Mostly, it is learning about human nature; how real people behave and react, as against how one would like them to behave and react. One can read and hear lot of idealistic stuff about how to make the world a better place, which would be found if it was based on an accurate observation of human nature, ” 学习做一个明智的人基本上就是学习什么是不可能的，学习很可能但又很困难的东西以至于不值得一个人为了达到目标而付出所有的努力。主要是了解人性;真实的人的行为和反应，以及人们希望他们的行为和反应。人们可以读到和听到很多关于如何让世界变得更美好的理想主义的东西，如果对人类本性的准确观察就能发现这些东西。由此判断出作者开始相信一个人必须用智慧来决定什么是最好的事情。故选B项。