Whileintegrasedeletesanimmunecell'sgeneticmaterialandreplacesitwithitsown,itactslike________inawordprocessor.

Without regular supplies of some hormones our capacity to behave would be seriously impaired; without others we would soon die. Tiny amounts of some hormones can modify moods and actions, our inclination to eat or drink, our aggressiveness or submissiveness, and our reproductive and parental behavior. And hormones do more than influence adult behavior; early in life they help to determine the development of bodily form and may even determine an individual’s behavioral capacities. Later in life the changing outputs of some endocrine glands and the body’s changing sensitivity to some hormones are essential aspects of the phenomena of aging.

Communication within the body and the consequent integration of behavior were considered the exclusive province of the nervous system up to the beginning of the present century. The emergence of endocrinology as a separate discipline can probably be traced to the experiments of Bayliss and Starling on the hormone secretion. This substance is secreted from cells in the intestinal walls when food enters the stomach; it travels through the bloodstream and stimulates the pancreas to liberate pancreatic juice, which aids in digestion. By showing that special cells secret chemical agents that are conveyed by the bloodstream and regulate distant target organs or tissues. Bayliss and starling demonstrated that chemical integration could occur without participation of the nervous system.

The term “hormone” was first used with reference to secretion. Starling derived the term from the Greek hormone, meaning “to excite or set in motion. The term “endocrine” was introduced shortly thereafter “Endocrine” is used to refer to glands that secret products into the bloodstream. The term “endocrine” contrasts with “exocrine”, which is applied to glands that secret their products though ducts to the site of action. Examples of exocrine glands are the tear glands, the sweat glands, and the pancreas, which secrets pancreatic juice through a duct into the intestine. Exocrine glands are also called duct glands, while endocrine glands are called ductless.

1.What is the author’s main purpose in the passage?

A.To explain the specific functions of various hormones.

B.To provide general information about hormones.

C.To explain how the term “hormone” evolved.

D.To report on experiments in endocrinology.

2.The passage supports which of the following conclusions?

A.The human body requires large amounts of most hormones.

B.Synthetic hormones can replace a person’s natural supply of hormones if necessary.

C.The quantity of hormones produced and their effects on the body are related to a person’s age.

D.The short child of tall parents very likely had a hormone deficiency early in life.

3.It can be inferred from the passage that before the Bayliss and Starling experiments, most people believed that chemical integration occurred only___.

A.during sleep.

B.in the endocrine glands.

C.under control of the nervous system.

D.during strenuous exercise.

4.The word “liberate” could best be replaced by which of the following?

A.Emancipate B.Discharge C.Surrender D.Save

5.According to the passage another term for exocrine glands is___.

A.duct glands

B.endocrine glands

C.ductless glands

D.intestinal glands.

Thefirstparagraphisintendedto________.

Part V Writing

写作指导

这是一篇描写文 (Description)。用通俗的话说，描写文就是用文字给人物、地点、景物画象。一篇描写文主要是通过所感受的细节——所见所闻发展而来的。在写人 时，不仅仅要用细节描写其外貌，而要注重通过他的言行来表现其人物性格、思想和品德，更要抓住他区别于他人的性格特点，这样就容易给读者留下深刻的印象。短文的第一、二段叙述故事发生的时间、地点，故事发生的原因及故事所涉及的人物。文章的三、四、五段描写的是人物的外貌，穿着及性格特点。通过对人物言行 的简单描写来揭示主人翁的助人为乐的高尚精神。短文的最后一段，要用一句话概括作者对主人翁的看法： A good guy。文章有描述，有议论，要加叙加议，有血有肉，上下文连贯要紧密，首尾要呼应，人和事要给人们留下深刻印象。

What does the future hold for the problem of housing? A good deal depends, of course, on the meaning of “future”. If one is thinking in terms of science fiction and the space age, it is at least possible to assume that man will have solved such trivial and earthly problems as housing. Writers of science fiction, from H.G. Wells onwards, have had little to say on the subject. They have conveyed the suggestion that men will live in great comfort, with every conceivable apparatus to make life smooth, healthy and easy, if not happy. But they have not said what his house will be made of. Perhaps some new building material, as yet unimagined, will have been discovered or invented at least. One may be certain that bricks and mortar(泥灰，灰浆) will long have gone out of fashion.

But the problems of the next generation or two can more readily be imagined. Scientists have already pointed out that unless something is done either to restrict the world’s rapid growth in population or to discover and develop new sources of food (or both), millions of people will be dying of starvation or at the best suffering from underfeeding before this century is out. But nobody has yet worked out any plan for housing these growing populations. Admittedly the worst situations will occur in the hottest parts of the world, where housing can be light structure or in backward areas where standards are traditionally low. But even the minimum shelter requires materials of some kind and in the teeming, bulging towns the low-standard “housing” of flattened petrol cans and dirty canvas is far more wasteful of ground space than can be tolerated.

Since the war, Hong Kong has suffered the kind of crisis which is likely to arise in many other places during the next generation. Literally millions of refugees arrived to swell the already growing population and emergency steps had to be taken rapidly to prevent squalor(肮脏)and disease and the spread crime. The city is tackling the situation energetically and enormous blocks of tenements(贫民住宅)are rising at an astonishing aped. But Hong Kong is only one small part of what will certainly become a vast problem and not merely a housing problem, because when population grows at this rate there are accompanying problems of education, transport, hospital services, drainage, water supply and so on. Not every area may give the same resources as Hong Kong to draw upon and the search for quicker and cheaper methods of construction must never cease.

1.What is the author’s opinion of housing problems in the first paragraph?

A.They may be completely solved at sometime in the future.

B.They are unimportant and easily dealt with.

C.They will not be solved until a new building material has been discovered.

D.They have been dealt with in specific detail in books describing the future.

2.The writer is sure that in the distant future ___.

A.bricks and mortar will be replaced by some other building material.

B.a new building material will have been invented.

C.bricks and mortar will not be used by people who want their house to be fashionable.

D.a new way of using bricks and mortar will have been discovered.

3.The writer believes that the biggest problem likely to confront the world before the end of the century ___.

A.is difficult to foresee.

B.will be how to feed the ever growing population.

C.will be how to provide enough houses in the hottest parts of the world.

D.is the question of finding enough ground space.

4.When the writer says that the worst situations will occur in the hottest parts of the world or in backward areas, he is referring to the fact that in these parts ___.

A.standards of building are low.

B.only minimum shelter will be possible.

C.there is not enough ground space.

D.the population growth will be the greatest.

5.Which of the following sentences best summarizes Paragraph 3?

A.Hong Kong has faced a serious crisis caused by millions of refugees.

B.Hong Kong has successfully dealt with the emergency caused by millions of refugees.

C.Hong Kong’s crisis was not only a matter of housing but included a number of other problems of population growth.

D.Many parts of the world may have to face the kind of problems encountered by Hong Kong and may find it much harder to deal with them.