18．Are some people born clever，and others born stupid？Or is intelligence developed by our environment and our experience？Strangely enough，the answer to these questions is yes．To some degree our intelligence is given to us at birth，and no amount of education can make a genius out of a child born with low intelligence．On the other hand，a child who lives in a boring environment will develop his intelligence less than one who lives in rich and different surroundings．Thus the limits of persons'intelligence are fixed at birth，and whether or not he reaches those limits will depend on his environment．This idea，now held by most experts，can be supported in a number of ways．
It is easy to show that intelligence is to some degree something we are born with．The closer the blood relationship between two people，the closer they are likely to be intelligent．Thus if we take two unrelated people at random from population，it is likely that their degree of intelligence will be completely different．If，on the other hand，we take two twins，they are very likely to be as intelligent as each other．Relations like brothers and sisters，parents and children，usually have similar intelligence，and this clearly suggests that intelligence depends on birth．
Imagine now that we take two identical twins and put them in different environments．We might send one，for example，to a university and the other to a factory where the work is boring．We would soon find differences in intelligence developing，and this shows that environment as well as birth plays a part．This conclusion is also suggested by the fact that people who live in touch with each other，but who are not related at all are likely to have similar degree of intelligence．
67．If a child is born with low intelligence，he canC．
A．become a genius
B．not reach his intelligence in his life
C．reach his intelligence limits in rich surroundings
D．still become a genius if he should be given special education
68．In Paragraph 2，the underlined sentence"if we take two unrelated people at random from population"means"A．"
A．if we pick any two persons
B．if we take out two different persons
C．if we choose two persons who have relations
D．if we choose two persons with different intelligence
69．The example of the twins going to a university and to a factory separately showsD．
A．the part that birth plays
B．the importance of their relations
C．the importance of their intelligence
D．the role of environment on intelligence
70．The best title of the passage can be"B"．
A．Surroundings B．Intelligence C．Dependence on Environment D．Effect of Education．
分析 本文属于说明文阅读，作者通过这篇文章主要向我们描述了影响智力的两个因素，智力范围是天生的，和他是否达到这些限制将取决于他的环境．
解答 67．C．细节理解题．根据文章第一段"Thus the limits of persons'intelligence are fixed at birth，and whether or not he reaches those limits will depend on his environment"可知如果一个孩子出生智力低下，他可以达到他的智能限制在富裕的环境里；故选C．
68．A．句意理解题．根据文章第二段"Thus if we take two unrelated people at random from population，it is likely that their degree of intelligence will be completely different"如果我们把两个不相干的人随机从人口，它是可能的，他们的智力程度将完全不同；可知句意为如果我们把两个不同的人；故选A．
69．D．细节理解题．根据文章最后一段"We would soon find differences in intelligence developing，and this shows that environment as well as birth plays a part"可知双胞胎分别上大学和工厂的例子表明环境对智力的作用；故选D．
70．B．主旨大意题．通读全文，可知文章主要讲述了影响智力的两个因素，智力范围是天生的，和他是否达到这些限制将取决于他的环境；因此最佳标题为智力；故选B．
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．
