2013英语四级阅读真题(2013年英语四级考试阅读备考材料是什么)

英语四级频道为您提供英语四级阅读的指导与练习。希望同学们四级顺利成功。　　There is evidence that the usual variety of high blood pressure is, in part, a familial disease. Since families have similar genes as well as similar environments, familial diseases could be due to shared genetic influences, to shared environmental factors, or to both. For some years, the role of one

environment factor commonly shared by families, namely dietary salt (i.e., sodium chloride), has been studied at Brookhaven National Laboratory. These studies suggest that long excess salt intake can lead to high blood pressure in man and animals. Some individuals, however, and some rats consume large amounts of salt without developing high blood pressure. No matter how strictly all environmental factors were controlled in these experiments, some salt-fed animals never developed hypertension whereas a few rapidly developed very severe hypertension followed by early death. These marked variations were interpreted to result from differences in genetic constitution.

By mating long successive generations of those animals that failed to develop hypertension from salt intake, a resistant strain (the " R" strain) has been evolved in which consumption of large quantities of salt fails to influence the blood pressure significantly. In contrast, by mating only animals that quickly develop hypertension from salt, sensitive strain (the "S" strain) has also been developed.

The availability of these two strains permits investigations possible. They provide a plausible laboratory model on which to investigate some clinical aspects of the human hypertension. More important, there might be the possibility of developing methods by which genetic susceptibility (敏感性) of human beings to high blood pressure can be defined without waiting for its appearance. Radioactive sodium 22 was an important "tool" in working out the characteristics of the sodium chloride metabolism.

21. The study of the effects of salt on high blood pressure was carried out_______.

A. as members of the same family tend to use similar amounts of salt

B. to explore the long-term use of a sodium based substance

C. because it was proven that salt caused high blood pressure

D. because of the availability of chemically pure salt and its derivatives

22. The main difference between "S" and "R" rats is their_______.

A. need for sodium 22 B. rate of mating

C. reaction to salt D. type of blood

23. We can infer from the article that sodium 22 can be used to_______.

A. control high blood pressure

B. cure high blood pressure caused by salt

C. tell the "S" rats from the "R" rats

D. determine what a sodium chloride metabolism is like

24. The most beneficial results of the research might be_______.

A. development of diets free of salt

B. an early cure for high blood pressure

C. control of genetic agents that cause high blood pressure

D. the early identification of potential high blood pressure victims

25. Which of the statements best relates the main idea of this article?

A. When salt is added rats and human beings react similarly.

B. The near future will see a cure for high blood pressure.

C. The medical field is desperately in need of research.

D. A tendency toward high blood pressure may be a hereditary factor.

21. A 22. C 23. D 24. D 25. D

  相关文章:

   70.gas/gs/n.①气体②煤气③汽油④毒气vt.①用毒气毒(死)②(up)给(汽车)加油【考点】steponthegas表示“踩油门，加大油门”。71.gasoline/.gs`lin，`gslin/n.汽油72.gaze/geiz/v./n.凝视，注视【考点】g

   大学英语六级听力备考需要掌握一些六级高频词汇，关于英语六级听力练习，是整个备考中比较难下手的一部分，今天四六级为大家分享英语六级听力练习：就餐类，希望对您有所帮助。微信公众号【四六级】丨官方微博【@四六级培训】英语六级听力练习：就餐类waiter/waitress男/女服务员pork猪肉order点菜beefsteak

   正在准备2020年6月英语六级考试的小伙伴们一定有不少同学还在困惑如何高效备考，尽管有一些解题方法及答题技巧，但这都是建立在一定的词汇量基础之上的。当同学们掌握了一定的单词量之后，就会发现在做题的时候很多之前的小问题都会迎刃而解。今天四

   2021年上半年大学英语四六级考试已经结束，各位参加12月四级考试的小伙伴该提前做准备了，四六级网小编为大家整理2021年12月大学英语四级阅读题练习，希望对大家的四级考试阅读题有帮助~Asubjectwhichseemstohavebeeninsufficientlystudiedbydoctorsandpsychologistsistheinflue

   1.条件句中虚拟语气的形式从句中提出一种与客观现实不相符或根本不可能存在的条件，主句会产生的一种不可能获得的结果。条件句中的虚拟语气根据不同的时间有三种不同的形式。时间从句谓语形式主句谓语形式将来动词过去式(be用we