公共英语等级考试模拟公共英语PETS一级标准预测及参考2

公共英语(PETS)一级标准预测试卷及参考答案2The WastelandA new catastrophe faces Afghanistan. The American bombing campaign is conspiring with years of civil conflict and drought to create an environmental crisis.Humanitarian and political concerns are dominating the headlines. But they are also masking the disappearance of the countrys once rich habitat and wildlife, which are quietly being crushed by war. The UN is dispatching a team of investigators to the region next month to evaluate the damage. “A health environment is a prerequisite for rehabilitation,” says Klaus Topfer, head of the UN environment Programme.Much of south-east Afghanistan was once lush forest watered by monsoon rains. Forests now cover less than 2 per cent of the country. “The worst deforestation occurred during Talibab rule, when its timber mafia denuded forests to sell to Pakistani markets,” says Usman Qazi, an environmental consultant based in Quetta, Pakistan. And the intense bombing intended to flush out the last of the Taliban troops is destroying or burning much of what remains.The refugee crisis is also wrecking the environment, and much damage may be irreversible. Forests and vegetation are being cleared for much-needed farming, but the gains are likely to be only short-term. “Eventually the land will be unfit for even the most basic form of agriculture,” warns hammad Naqi of the World Wide Fund for Nature in Pakistan. Refugeesaround 4 million as the last countare also cutting into forests for firewood.The hail of bombs falling on Afghanistan is making life particularly hard for the countrys wildlife. Birds such as the pelican and endangered Siberian crane cross eastern Afghanistan as they follow one of the worlds great migratory thoroughfares from Siberia to Pakistan and India. But the number of the birds flying across the region has dropped by a staggering 85 per cent. “Cranes are very sensitive and they do not use the route if they see any danger,” says Ashiq Ahgmad, an environmental scientist for the WWF in Peshawar, Pakistan, who has tracked the collapse of the birds migration this winter.The rugged mountains also usually provide a safe have for mountain leopards, gazelles, bears and Marco Polo sheepthe worlds largest species. “The same terrain that allows fighters to strike and disappear back into the hills has also historically enabled wild life to survive,” says Peter Zahler of the Wildlife Conservation society, based in New York. But he warns they are now under intense pressure from the bombing and invasions of refugees and fighters.For instance, some refugees are hunting rare snow leopards to buy a safe passage across the border. A single fur can fetch $2,000 on the black market, says Zahler. Only 5,000 or so snow leopards are thought to survive in central Asia, and less than 0 in Afghanistan, their numbers already decimated by extensive hunting and smuggling into Pakistan before the conflict. Timber, falcons and medicinal plants are also being smuggled across the border. The Talibab once controlled much of this trade, but the recent power vacuum could exacerbate the problem.Bombing will also leave its mark beyond the obvious craters. Defence analysts says that while depleted uranium has been used less in Afghanistan that in the Kosovo conflict, conventional explosives will litter the country with pollutants. They contain toxic compounds such as cyclonite, a carcinogen, and rocket propellants contain perchlorates, which damage thyroid glands.1. All of the following are causes of the environmental crisis in Afghanistan EXCEPTA. American bombing.B. heavy monsoon rains.C. years of lack of rain.D. fighting among the Afghanis.2. According to the passage, the main cause of the loss of the countrys forests isA. the flooding caused by the monsoon rain.B. the intense bombing of the Taliban troops.C. the improper use of the trees for benefits during Taliban rule.D. the fire set to burn the forests by the Taliban troops.3. Most of the migratory bird no longer fly across Afghanistan to Pakistan and India becauseA. they change their route from time to time.B. some birds have collapsed while flying.C. they have been threatened by the bombs dropped on the country.D. they are scared by the big animals in the mountains.4. In which of the following ways do the refugees threaten the survival of such wild animals as the snow leopards?A. They hunt the animals for food.B. They fight in the rugged mountains that provide a haven for the animals.C. They hunt the animals to make profits.D. They drive the animals away from their homes in the mountains.5. Which of the following CANNOT be inferred from the last paragraph?A. Depleted uranium is not a kind of conventional explosives.B. Craters are not the only damage done by bombs.C. The conventional bombs are no less damaging to environment than the non-conventional ones.D. Fewer people were killed in bombing in Afghanistan than in Kosovo.Late-night DrinkingCoffee lovers beware. Having a quick “pick-me-up” cup of coffee late in the day will play havoc with your sleep. As well as being a stimulant, caffeine interrupts the flow of melatonin, the brain hormone that sends people into a sleep.Melatonin levels normally start to rise about two hours before bedtime. Levels then peak between 2 a.m. and 4 a.m., before falling again. “Its the neurohormone that controls our sleep and tells our body when to sleep and when to wake, ” says Maurice Ohayon of the Stanford Sleep Epidemiology Research Center at Stanford University in California. But researchers in Israel have found that caffeinated coffee halves the bodys levels of this sleep hormone.Lotan Shilo and a team at the Sapir Medical Center in Tel Aviv University found that six volunteers slept less well after a cup of caffeinated coffee than after drinking the same amount of decaf. On average, subjects slept 336 minutes per night after drinking caffeinated coffee, compared with 4 minutes after decaf. They also took half an hour to drop off4twice as long as usualand jigged around in bed twice as much.In the second phase of the experiment, the researchers woke the volunteers every three hours and asked them to give a urine sample. Shilo measured concentrations of a breakdown product of melatonin. The results suggest that melatonin concentrations in caffeine drinkers were half those in decaf drinkers. In a paper accepted for publication in Sleep Medicinc, the researchers suggest that caffeine blocks production of the enzyme that drives melatonin production.Because it can take many hours to eliminate caffeine from the body, Ohayon recommends that coffee lovers switch to decaf after lunch.1The author mentions “pick-me-up” to indicate thatA. melatonin levels need to be raised.B. neurohormone can wake us up.C. coffee is a stimulant.D. decaf is a caffeinated coffee.2. Which of the following tells us how caffeine affects sleep?A. Caffeine blocks production of the enzyme that stops melatonin production.B. Caffeine interrupts the flow of the hormone that prevents people from sleeping.C. Caffeine halves the bodys levels of sleep hormone.D. Caffeine stays in the body for many hours.3. What does paragraph 3 mainly discuss?A. Different effects of caffeinated coffee and decaf on sleep.B. Different findings of Lotan Shilo and a team about caffeine.C. The fact that the subjects slept 4 minutes per night after drinking decaf.D. The evidence that the subjects took half an hour to fall asleep.4.What does the experiment mentioned in paragraph 4 prove?A. There are more enzymes in decaf drinkers urine sample.B. there are more melatonin concentrations in caffeine drinkers urine sample.C. Decaf drinkers produce less melatonin.D. Caffeine drinkers produce less sleep hormone.5. The author of this passage probably agrees thatA. coffee lovers sleep less than those who do not drink coffee.B. we should not drink coffee after supper.C. people sleep more soundly at midnight than at 3 a.m.D. if we feel sleepy at night, we should go to bed immediately.Pool WatchSwimmers can drown in busy swimming pools when lifeguards fail to notice that they are in trouble. The Royal Society for the Prevention of Accidents says that on average people drown in British pools each year, but many more suffer major injury after getting into difficulties. Now a French company has developed an artificial intelligence system called Poseidon that sounds the alarm when it sees someone in danger of drowning.When a swimmer sinks towards the bottom of the pool, the new system sends an alarm signal to a poolside monitoring station and a lifeguards paper. In trials at a pool in Ancenis, near Nantes, it saved a life within just a few months, says Alistair MeQuade, a spokesman for its maker, Poseidon Technologies.Poseidon keeps watch through a network of underwater and overheard video cameras. AI software analyses the images to work out swimmers trajectories. To do this reliably, it has to tell the difference between a swimmer and the shadow of someone being cast onto the bottom or side of the pool. “The underwater environment is a very dynamic one, with many shadows and reflections dancing around.” Says McQuade.The software does this by “projecting” a shape in its field of view onto an image of the far wall of the pool. It does the same with an image from another camera viewing the shape from a different angle. If the two projections are in the same position, the shape is identified as a shadow and is ignored. But if they are different, the shape is a swimmer and so the system follows its trajectory.To pick out potential drowning victims, anyone in the water who starts to descend slowly is added to the softwares “pre-alert” list, says McQuade. Swimmers who then stay immobile on the pool bottom for 5 seconds or more are considered in danger of drowning. Poseidon double-checks that the image really is of a swimmer, not a shadow, by seeing whether it obscures the pools floor texture when viewed from overhead. If so, it alerts the lifeguard, showing the swimmers location on a poolside screen.The first full-scale Poseidon system will be officially opened next week at a pool in High Wycombe. Buckinghamshire. One man