12．During the 19th century，scientists found that when certain parts of the brain of a person were hurt，he would lose the power of doing certain things．And so，people thought that each part of the brain does a different job．But modern research has discovered that this is not so，for it is not easy to show exactly what each part of the brain does．
In the past fifty years there has been a great increase in the amount of researches done on the brain．Scientists have found out the way the brain works is not so simple as people in general may think．Chemists tell us that about 100，000 chemical changes take place in the brain every second．Some recent researches also suggest that we can remember everything that happens to us．We may not be able to think of the thing that happens to us．We may not be able to think of the things we have heard and seen，but they're all kept there in the storehouse of the human mind．
Earlier scientists thought that the power of one's brain got weaker and weaker as one grows older．But it is now thought that that is not true．As long as the brain is given plenty of exercise，it keeps its power．It has been proved that an old person who has always been active in the mind has a quicker mind than a young person who has only done physical work without using much of his brain．
60．In the 19th century，scientists found that a person would lose the power to do certain thingsD．
A．when he had drunk too much
B．after he did a quite different job
C．if he had been greatly frightened
D．if certain parts of his brain were hurt
61．Scientists today are still unable to show exactlyA．
A．what each part of the brain is doing
B．which part of the brain is the most important
C．whether each part of the brain does the same work
D．how many chemical changes take place in the brain each second
62．It has been found that the brain usually worksC．
A．in a very simple way
B．a little now and a little then
C．without any rest all day long
D．in a fairly complicated （复杂的） way
63．Which of the following is NOT true？C
A．Scientists are working hard to solve the mysteries of the brain．
B．As many as six million changes take place in the brain every minute．
C．A young man doing physical work is sure to have a much slower mind．
D．Even an old man may have a quick mind only if his brain is given much exercise．
分析 本文介绍了如果给我们的大脑足够的练习，人的大脑就会做更多的事情，而且这个不会随着年龄的变化而变化．
解答 DACC
60 D 细节题．根据文章第一段1，2行During the 19th century，scientists found that when certain parts of the brain of a person were hurt，he would lose the power of doing certain things．说明当人的大脑的一部分损坏的时候，身体的一部分的功能也失去了．D正确．
61 A 细节题．根据第一段最后2行But modern research has discovered that this is not so，for it is not easy to show exactly what each part of the brain does．说明现在的科学家还没有彻底搞清楚这样的问题，故A正确．
62 C 推理题．根据第二段3，4行Chemists tell us that about 100，000 chemical changes take place in the brain every second．说明人的大脑每秒钟都在运行，没有休息的时间．故C正确．
63 C 细节题．根据文章最后一段It has proved that an old person who has always been active in the mind has a quicker mind than a young person who has done physical work without using much of his brain．说明如果不运用脑子来思考，那么一定会思维缓慢．如果用脑子思考了，就会思维迅速．故C项的说法不准确．
点评 考察学生的细节理解和推理判断能力，做细节理解题时一定要找到文章中的原句，和题干进行比较，再做出正确的选择．在做推理判断题不要以个人的主观想象代替文章的事实，要根据文章事实进行合乎逻辑的推理判断．
