Many of us believe that a person‘s mind becomes less active as he grows older. But this is not true， according to Dr Jarvik， professor of psychiatry at the University of California. She has studied the mental functioning of aging persons for several years. For example， one of her studies concerns 136 pairs of identical twins， who were first examined when they were already 60 years old. As Dr Jarvik continued the study of the twins into their 70s and 80s， their minds did not generally decline as was expected.外语学习网
However， there was some decline in their psycho-motor speed. This means that it took them longer to accomplish mental tasks than it used to. But when speed was not a factor， they lost very little intellectual ability over the years. In general， Dr Jarvik‘s studies have shown that there is no decline in knowledge or reasoning ability. This is true not only with those in their 30s and 40s， but with those in their 60s and 70s as well.
It is true that older people themselves often complain that their memory is not as good as it once was. However， much of what we call “loss of memory” is not that at all. There usually was incomplete learning in the first place. For example， the older person perhaps had trouble hearing， or poor vision， or inattention， or was trying to learn the new thing at too fast a pace. In the cases where the older person‘s mind really seems to decay， it is not necessarily a sign of decay due to old age. Often it is simply a sign of a depressed emotional state.
16.This passage is mainly about ____.
A） how Dr Jarvik studied mental functioning of the twins.
B） what caused mental decay.
C） the results evidenced by Dr Jarvik‘s studies.
D） the difference between middle – aged and older persons
答案： C
解析： 大意题。本文主要向读者传达了人的记忆和分析能力不是随着年龄的增大而消退，主要是通过。Dr Jarvik的研究成果来显示的。其它选项不是文章的主旨意思。
17. The word “psychiatry” in paragraph 1 most probably means ____.
A） the study of human behavior.
B） the study of disease of the mind.
C） the study of problems with aging persons.
D） the study of twins growth.
答案： B
解析： 大意题。同上题的解释。主要的是disease of the mind和年龄的区别。
18. A long – term study of 136 pairs of twins showed that ____.
A） they lost a little ability to reason over the years.
B） the only factor which declined over the years was their speed with which to perform mental tasks.
C） their memory was not as good as it had once been.
D） their minds became is not considered as they grew older.
答案： B
解析： 细节和推论。文章的第一段最后一句和第２段的前两句都是说明这样的一个实验说明研究结果。即，仅仅和速度有关系，课文的下面部分也相应作了解释。
