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When was the last time you saw a frog? Chances are, if you live in a city, you have not seen one for some time. Even in wet areas once teeming with frogs and toads, it is BEComing less and less easy to find those slimy, hopping and sometimes poisonous members of the animal kingdom. All over the world, and even in remote parts of Australia, frogs are losing the ecological battle for survival, and biologists are at a loss to explain their demise. Are amphibians simply oversensitive to changes in the ecosystem? Could it be that their rapid decline in numbers is signaling some coming environmental disaster for us all? This frightening scenario is in part the consequence of a dramatic increase over the last quarter century in the development of once natural areas of wet marshland; home not only to frogs but to all manner of wildlife. However, as yet, there are no obvious reasons why certain frog species are disappearing from rainforests in Australia that have barely been touched by human hand. The mystery is unsettling to say the least, for it is known that amphibian species are extremely sensitive to environmental variations in temperature and moisture levels. The danger is that planet Earth might not only lose a vital link in the ecological food chain (frogs keep populations of otherwise pestilent insects at manageable levels), but we might be increasing our output of air pollutants to levels that may have already become irreversible. Frogs could be inadvertently warning us of a catastrophe.

An example of a species of frog that, at far as is known, has become extinct, is the platypus frog. Like the well-known Australian mammal it was named after, it exhibited some very strange behaviour; instead of giving birth to tadpoles in the water, it raised its young within its stomach. The baby frogs

were actually born from out of their mother's mouth. Discovered in 1981, less than ten years later the frog had completely vanished from the crystal clear waters of Booloumba Creek near Queensland's Sunshine Coast. Unfortunately, this freak of nature is not the only frog species to have been lost in Australia. Since the 1970s, no less than eight others have suffered the same fate.

One theory that seems to fit the facts concerns the depletion of the ozone layer, a well documented phenomenon which has led to a sharp increase in ultraviolet radiation levels.The ozone layer is meant to shield the Earth from UV rays, but increased radiation may be having a GREater effect upon frog populations than previously believed. Another theory is that worldwide temperature increases are upsetting the breeding cycles of frogs.

TRUE/FALSE/NOT GIVEN

1.Frogs are disappearing only from city areas.

2.Frogs and toads are usually poisonous.

3.Biologists are unable to explain why frogs are dying.

4.The frogs' natural habitat is becoming more and more developed.

5.Attempts are being made to halt the development of wet marshland.

6.Frogs are important in the ecosystem because they control pests.

7.The platypus frog became extinct by 1991.

8.Frogs usually give birth to their young in an underwater nest.

9.Eight frog species have become extinct so far in Australia.

10.There is convincing evidence that the ozone layer is being depleted.

11.It is a fact that frogs' breeding cycles are upset by worldwide in creases in temperature.

Answer Keys：1.F 2.F 3.T 4.T 5.NG 6.T 7.T 8.NG 9.F 10.T 11.F

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Almost everyone with or without a computer is aware of the latest technological revolution destined to change forever the way in which humans communicate, namely, the Information Superhighway, best exemplified by the ubiquitous Internet. Already, millions of people around the world are linked by computer simply by having a modem and an address on the `Net', in much the same way that owning a telephone links us to almost anyone who pays a phone bill. In fact, since the computer connections are made via the phone line, the Internet can be envisaged as a network of visual telephone links. It remains to seen in which direction the Information Superhighway is headed, but many believeit is the educational hope of the future.

The World Wide Web, an enormous collection of Internet addresses or sites, all of which can be accessed for information, has been mainly responsible for the increase in interest in the Internet in the 1990s. Before the World Wide Web, the `Net' was comparable to an integrated collection of computerized typewriters, but the introduction of the `Web' in 1990 allowed not only text links to be made but also graphs, images and even video.

A Web site consists of a `home page', the first screen of a particular site on the computer to which you are connected, from where access can be had to other subject related `pages'(or screens) at the site and on thousands of other computers all over the world. This is achieved by a process called `hypertext'. By clicking with a mouse device on various parts of the screen, a person connected to the `Net' can go traveling, or surfing' through a of the screen, a person connected to the `Net' can go traveling, or `surfing' through a web of pages to locate whatever information is required.

Anyone can set up a site; promoting your club, your institution, your company's products or simply yourself, is what the Web and the Internet is all about. And what is more, information on the Internet is not owned or controlled by any one organization. It is, perhaps, true to say that no one and therefore everyone owns the `Net'. BECause of the relative freedom of access to information, the Internet has often been criticised by the media as a potentially hazardous tool in the hands of young computer users. This perception has proved to be largely false however, and the vast majority of users both young and old get connected with the Internet for the dual purposes for which it was intended - discovery and delight.

TRUE/FALSE/NOT GIVEN

1.Everyone is aware of the Information Superhighway.

https://www.sodocs.net/doc/f78333149.html,ing the Internet costs the owner of a telephone extra money.

3.Internet computer connections are made by using telephone lines.

4.The World Wide Web is a network of computerised typewriters.

5.According to the author, the Information Superhighway may be the future hope of education.

6.The process called`hypertext'requires the use of a mouse device.

7.The Internet was created in the 1990s.

8.The `home page'is the first screen of a `Web'site on the `Net'.

9.The media has often criticised the Internet because it is dangerous.

10. The latest technological revolution will change the way humans communicate.

1.F

2.NG

3.T

4.F

5.T

6.T

7.F

8.T

9.F 10.T

2014年雅思阅读模拟试题(3)

1. The failure of a high-profile cholesterol drug has thrown

a spotlight on the complicated machinery that regulates cholesterol levels. But many researchers remain confident that drugs to boost levels of ’good’ cholesterol are still one of the most promising means to combat spiralling heart disease.

2. Drug company Pfizer announced on 2 December that it was cancelling all clinical trials of torcetrapib， a drug designed to raise heart-protective high-density lipoproteins (HDLs)。In a trial of 15000 patients， a safety board found that more people died or suffered cardiovascular problems after taking the drug plus a cholesterol-lowering statin than those in a control group who took the statin alone.

3. The news came as a kick in the teeth to many cardiologists because earlier tests in animals and people suggested it would lower rates of cardiovascular disease. “There have been no red flags to my knowledge，” says John Chapman， a specialist in lipoproteins and atherosclerosis at the National Institute for Health and Medical Research (INSERM) in Paris who has also studied torcetrapib. “This cancellation came as a complete shock.”

4. Torcetrapib is one of the most advanced of a new breed of drugs designed to raise levels of HDLs， which ferry cholesterol out of artery-clogging plaques to the liver for removal from the body. Specifically， torcetrapib blocks a protein called cholesterol ester transfer protein (CETP)，which normally transfers the cholesterol from high-density lipoproteins to low density， plaque-promoting ones. Statins，in contrast， mainly work by lowering the ’bad’ low-density lipoproteins.

Under pressure

5. Researchers are now trying to work out why and how the drug backfired， something that will not become clear until the clinical details are released by Pfizer. One hint lies in evidence from earlier trials that it slightly raises blood pressure in some patients. It was thought that this mild problem would be offset by the heart benefits of the drug. But it is possible that it actually proved fatal in some patients who already suffered high blood pressure. If blood pressure is the explanation， it would actually be good news for drug developers because it suggests that the problems are specific to this compound. Other prototype drugs that are being developed to

block CETP work in a slightly different way and might not suffer the same downfall.

6. But it is also possible that the whole idea of blocking CETP is flawed， says Moti Kashyap， who directs atherosclerosis research at the VA Medical Center in Long Beach， California. When HDLs excrete cholesterol in the liver， they actually rely on LDLs for part of this process. So inhibiting CETP， which prevents the transfer of cholesterol from HDL to LDL， might actually cause an abnormal and irreversible accumulation of cholesterol in the body. “You’re blocking a physiologic mechanism to eliminate cholesterol and effectively constipating the pathway，” says Kashyap.

Going up

7. Most researchers remain confident that elevating high density lipoproteins levels by one means or another is one of the best routes for helping heart disease patients. But HDLs are complex and not entirely understood. One approved drug，called niacin， is known to both raise HDL and reduce cardiovascular risk but also causes an unpleasant sensation of heat and tingling. Researchers are exploring whether they can bypass this side effect and whether niacin can lower disease risk more than statins alone. Scientists are also working on

several other means to bump up high-density lipoproteins by，for example， introducing synthetic HDLs. “The only thing we know is dead in the water is torcetrapib， not the whole idea of raising HDL，” says Michael Miller， director of preventive cardiology at the University of Maryland Medical Center，Baltimore.

Questions 1-7

This passage has 7 paragraphs 1-7.

Choose the correct heading for each paragraph from the list of headings below.

Write the correct number i-ix in boxes 1-7 on your answer sheet.

List of Headings

i. How does torcetrapib work?

ii. Contradictory result prior to the current trial

iii. One failure may possibly bring about future success iv. The failure doesn’t lead to total loss of confidence v. It is the right route to follow

vi. Why it’s stopped

vii. They may combine and theoretically produce ideal result

viii. What’s wrong with the drug

ix. It might be wrong at the first place

Questions 7-13

Match torcetrapib，HDLs，statin and CETP with their functions (Questions 8-13)。。

Write the correct letter A， B， C or D in boxes 8-13 on your answer sheet.

NB You may use any letter more than once.

7.It has been administered to over 10，000 subjects in a clinical trial.

8.It could help rid human body of cholesterol.

9.Researchers are yet to find more about it.

10. It was used to reduce the level of cholesterol.

11. According to Kashyap， it might lead to unwanted result if it’s blocked.

12. It produced contradictory results in different trials.

13. It could inhibit LDLs.

List of choices

A. Torcetrapic

B. HDLS

C. Statin

D. CETP

Suggested Answers and Explanations

1. vi

2. ii

3. vii 本段介绍了torcetrapib和statin的治病原理，但是同时短语“in contrast”与之前第二段后半段的内容呼应，暗示了这两种药在理论上能相辅相成，是理想的搭配。第一个选项无法涵盖整段意义，故选择i是错误的。

4. iii 本段分析了可能导致torcetrapibl临床试验失败的原因，后半段指出如果以上推测正确，那么未来的药物可借鉴这个试验，设法避免torcetrapib的缺陷，研制出有效的药物。viii选项无法涵盖后半段的意思。

5. ix 见首句。

6. v

7. A 见第二段。题目中administer一词意为“用药”，subject 一词为“实验对象”之意。

8. B 见第四段“… to raise levels of HDLs， which ferry cholesterol out of artery- clogging plaques to the liver for removal from the body.”即HDLs的作用最终是将 choleserol清除出人体：“… for removal from the body”。

9. B 见第四段“But HDLs are complex and not entirely understood.”

10. C 见第二段“… plus a cholesterol-lowering statin”，即statin是可以降低cholesterol的。

11. D 见第六段“So inhibiting CETP，… might actually cause an abnormal and irreversible accumulation of cholesterol in the body.

12. A 见第三段。

13. C 见第四段“Statins， in contrast， mainly work by lowering the ’bad’ low-density lipoproteins

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雅思精讲阅读班精讲班第7讲讲义 Questions 22-24 What is a dinosaur? A. Although the name dinosaur is derived from the Greek for “terrible lizard”, dinosaurs were not, in fact, lizards at all. Like lizards, dinosaurs are included in the class Reptilia, or reptiles, one of the five main classes of Vertebrata, animals with backbones. However, at the next level of classification, within reptiles, significant differences in the skeletal anatomy of lizards and dinosaurs have led scientists to place these groups of animals into two different superorders: Lepidosauria, or lepidosaurs, and Archosauria, or archosaurs. B. Classified as lepidosaurs are lizards and snakes and their prehistoric ancestors. Included among the archosaurs, or “ruling reptiles”, are prehistoric and modern crocodiles, and the now extinct thecondonts, pterosaurs and dinosaurs. Paleontologists believe that both dinosaurs and crocodiles evolved, in the later years of the Triassic Period (c. 248-208 million years ago), from creatures called pseudosuchian thecodonts. Lizards, snakes and different types of thecondont are believed to have evolved earlier in the Triassic Period from reptiles known as eosuchians. C. The most important skeletal differences between dinosaurs and other archosaurs are in the bones of the skull, pelvis and limbs. Dinosaur skulls are found in a great range of shapes and sizes, reflecting the different eating habits and lifestyles of a large and varied group of animals that dominated life on Earth for an extraordinary 165 million years. However, unlike the skulls of any other known animals, the skulls of dinosaurs had two long bones known as vomers. These bones extended on either side of the head, from the front of the snout to the level of the holes in the skull known as the antorbital fenestra, situated in front of the dinosaur’s orbits or eyesockets. D. All dinosaurs, whether large or small, quadrupedal or bipedal, fleet-footed or slow-moving, shared a common body plan. Identification of this plan makes it possible to differentiate dinosaurs from any other types of animal, even other archosaurs. Most significantly, in dinosaurs, the pelvis and femur had evolved so that the hind limbs were held vertically beneath the body, rather than sprawling out to the sides like the limbs of a lizard. The femur of a dinosaur had a sharply in-turned neck and a ball-shaped head, which slotted into a fully open acetabulum or hip socket. A supra-acetabular crest helped prevent dislocation of the femur. The position of the knee joint, aligned below the acetabulum, made it possible for the whole hind limb to swing backwards and forwards. This unique combination of features gave dinosaurs what is know as a “fully improved gait”. Evolution of this highly efficient method of walking also developed in mammals,