Part IV Reading Comprehension (Reading in Depth) (25 minutes)

　　Section A

　　Directions: In this section, there is a short passage with 5 questions or incomplete statements. Read the passage carefully. Then answer the questions or complete the statements in the fewest possible words on Answer Sheet 2.

　　Questions 47 to 51 are based on the following passage.

　　Scientists say they have high hopes for a drug that could one day provide a new form of treatment for HIV-AIDS. A compound, which interferes with an elusive protein used by the HIV virus to infect human cells, has worked extremely well in monkeys. If the drug proves effective in human trials, scientists say, it could bolster(加强)the effectiveness of two existing AIDS drugs, particularly in fighting drug-resistant strains of the virus.

　　Researchers at the pharmaceutical(制药的)company Merck are very excited about an experimental drug, which has worked as well in monkeys infected with a primate version of the virus as any of the existing anti-AIDS drugs.

　　It works by blocking one of three proteins, or enzymes, the HIV virus uses to gain entrance into and infect human immune system cells.

　　Inhibitor drugs have been developed to block two of the proteins, to slow progression of the disease after infection. They have become standard therapy as a "cocktail" for people infected with HIV.

　　Those enzymes are reverse transcriptase (转录酶)and protease(蛋白酶). The first converts the virus' genetic material into that of its host cells. The second chops up the resulting larger proteins into smaller pieces, producing smaller viral particles that infect new cells.

　　The third prong of cellular attack is a protein called integrase(整合酶), which experts say has been harder to block. Once HIV fools host cells by changing its genetic information so it can enter them, integrase acts like a cut and paste operation in a word processor, deleting an immune cell's genetic material and replacing it with its own.

　　An integrase inhibitor would give doctors a third line of attack against HIV infection, according to virologist Daria Hazuda of the division of Virus and Cell Biology at Merck.

　　"This would offer a third class of anti-retroviral medications that can be combined with reverse transcriptase inhibitors and protease inhibitors. And since it is a new mechanism of action, these compounds are active against multi-drug resistant variants. So variants that are resistant to all current therapies have been selected in HIV-patients," she said.

　　Current anti-AIDS drugs eventually become resistant to therapy, or stop working, because the virus changes its shape.

　　While researchers are encouraged by the success with the compound's effectiveness in monkey trials, developing a drug that is equally effective in humans can be difficult.

　　Steven Young is executive director of the Department of Medicinal Chemistry at Merck. He says, if scientists find a compound that is equally effective in people, the company would ask U.S. regulators to speed approval of the drug.

　　"Yeah, I really think that's what we're hoping for," he said. "I mean, we need to get data that show it has robust anti-viral effects in people. And if we're able to get that data, I think we would petition for fast track status."

　　Dr. Young says an integrase inhibitor has the potential to prevent drug resistance.

　　"To ensure our best chance of preventing resistance, we would give this as part of a cocktail therapy," he added. "And I think it's really our plan that we would test this with reverse transcriptase inhibitors and protease inhibitors, as well."

　　47. If the drug proves effective in human trials, it could enhance the effectiveness of existing AIDS drugs in ________.

　　48. What has become standard cocktail therapy?

　　49. While integrase deletes an immune cell's genetic material and replaces it with its own, it acts like ________ in a word processor.

　　50. Why would anti-AIDS drugs stop working?

　　51. According to Steven Young, if scientists get the data that ________, they would petition for fast track status.

　　Section B

　　Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked [A], [B], [C] and [D]. You should decide on the best choice and mark the corresponding letter on Answer Sheet 2 with a single line through the center.

　　Passage One

　　Questions 52 to 56 are based on the following passage.

　　Occasional self-medication has always been part of normal living. The making and selling of drugs have a long history and are closely linked, like medical practice itself, with the belief in magic. Only during the last hundred years or so has the development of scientific techniques made it possible for some of the causes of symptoms to be understood, so that more accurate diagnosis has become possible. The doctor is now able to follow up the correct diagnosis of many illnesses with specific treatment of their causes. In many other illnesses, of which the causes remain unknown, it is still limited, like the unqualified prescriber, to the treatment of symptoms. The doctor is trained to decide when to treat symptoms only and when to attack the cause: this is the essential difference between medical prescribing and self-medication.

　　The advance of technology has brought about much progress in some fields of medicine, including the development of scientific drug therapy. In many countries public health organization is improving and people's nutritional standards have risen. Parallel with such beneficial trends have two adverse effects. One is the use of high-pressure advertising by the pharmaceutical industry, which has tended to influence both patients and doctors and has led to the overuse of drugs generally. The other is the emergence of the sedentary society with its faulty ways of life: lack of exercise, over-eating, unsuitable eating, insufficient sleep, excessive smoking and drinking. People with disorders arising from faulty habits such as these, as well as from unhappy human relationships, often resort to self-medication and so add the taking of pharmaceuticals to the list. Advertisers go to great lengths to catch this market.

　　Clever advertising, aimed at chronic sufferers who will try anything because doctors have not been able to cure them, can induce such faith in a preparation, particularly if steeply priced, that it will produce—by suggestion—a very real effect in some people. Advertisements are also aimed at people suffering from mild complaints such as simple colds and coughs, which clear up by themselves within a short time.

　　These are the main reasons why laxatives, indigestion remedies, painkillers, tonics, vitamin and iron tablets and many other preparations are found in quantity in many households. It is doubtful whether taking these things ever improves a person's health; it may even make it worse. Worse because the preparation may contain unsuitable ingredients; worse because the taker may become dependent on them; worse because they might be taken in excess; worse because they may cause poisoning, and worse of all because symptoms of some serious underlying cause may be masked and therefore medical help may not be sought.

　　52. The first paragraph is intended to ________.

　　[A] suggest that self-medication has a long history

　　[B] define what diagnosis means exactly

　　[C] praise doctors for their expertise

　　[D] tell the symptoms from the causes

　　53. Advertisements are aimed at people suffering from mild complaints because ________.

　　[A] they often watch ads on TV

　　[B] they are more likely to buy the drugs advertised

　　[C] they generally lead a sedentary life

　　[D] they don't take to sports and easily catch colds

　　54. Paragraphs 2 and 3 explain ________.

　　[A] those good things are not without side effects

　　[B] why clever advertising is so powerful

　　[C] why in modern times self-medication is still practised

　　[D] why people develop faulty ways of life

　　55. The author tells us in paragraph 4 ________.

　　[A] the reasons for keeping medicines at home

　　[B] people's doubt about taking drugs

　　[C] what kind of medicine people should prepare at home

　　[D] the possible harms self-medication may do to people

　　56. The best title for the passage would be ________.

　　[A] Medical Practice [B] Clever Advertising

　　[C] Self-Medication [D] Self-Treatment

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