剑7Test 1阅读Passage1真题及解析
READING PASSAGE 1
You should spend about 20 minutes on Questions 1-13, which are bad on Reading Passage 1 on the following pages.
Let’s Go Bats情侣头像非主流
A Bats have a problem: how to find their way around in the dark. They hunt at night, and cannot u light to help them find prey and avoid obstacles. You might say that this is a problem of their own making, one that they could avoid simply by changing their habits and hunting by day. But the daytime economy is already heavily exploited by other creatures such as birds. ③雷姆高清壁纸Given that there is a living to be made at night, and given that alternative daytime trades are thoroughly occupied, natural lection has favoured bats that make a go of the night-hunting trade. It is probable that the nocturnal trades go way back in the ancestry of all mammals.② In the time when the dinosaurs dominated the day
time economy, our mammalian ancestors probably only managed to survive at all becau they found ways of scraping a living at night.阜阳注册公司 南兰陵Only after the mysterious mass extinction of the dinosaurs about 65 million years ago were our ancestors able to emerge into the daylight in any substantial numbers.
B Bats have an engineering problem: how to find their way and find their prey in the abnce of light. ①Bats are not the only creatures to face this difficulty today. Obviously the night-flying incts that they prey on must find their way about somehow. Deep-a fish and whales have little or no light by day or by night. Fish and dolphins that live in extremely muddy water cannot e becau, although there is light, it is obstructed and scattered by the dirt in the water. Plenty of other modern animals make their living in conditions where eing is difficult or impossible.
C Given the questions of how to manoeuvre in the dark, what solutions might an engineer consider? The first one that might occur to him is to manufacture light, to u a lantern or a archlight. Fireflies and some fish (usually with the help of bacteria) have th
e power to manufacture their own light, but the process ems to consume a large amount of energy. Fireflies u their light for attracting mates. This doesnt require a prohibitive（费用，价格等）过高的 amount of energy: a male's tiny pinprick of light can be en by a female from some distance on a dark night, since her eyes are expod directly to the light source itlf. However, using light to find one's own way around requires vastly more energy, since the eyes have to detect the tiny fraction of the light that bounces off each part of the scene. The light source must therefore be immenly brighter if it is to be ud as a headlight to illuminate the path, than if it is to be ud as a signal to others. 阅读笔记的格式In any event, whether or not the reason is the energy expen, it ems to be the ca that, with the possible exception of some weird deep-a fish, no animal apart from man us manufactured light to find its way about.
D芦荟胶怎么使用 What el might the engineer think of? well, blind humans sometimes em to have an uncanny n of obstacles in their path. It has been given the name 'facial vision', becau blind people have reported that it feels a bit like the n of touch, on the face. One report tells of a totally blind boy who could ride his tricycle at good speed round the b
fixmelock near his home, using facial vision. Experiments showed that, in fact, facial vision is nothing to do with touch or the front of the face, although the nsation may be referred to the front of the face, like the referred pain in a phantom limb. The nsation of facial vision, it turns out, really goes in through the ears. Blind people, without even being aware of the fact, are actually using echoes of their own footsteps and of other sounds, to n the prence of obstacles. Before this was discovered, engineers had already built instruments to exploit the principle, for example to measure the depth of the a under a ship. ⑤After this technique had been invented, it was only a matter of time before weapons designers adapted it for the detection of submarines. Both sides in the Second world war relied heavily on the devices, under such code names as Asdic (British) and Sonar (American), as well as Radar (American) or RDF (British), which us radio echoes rather than sound echoes.
E The Sonar and Radar pioneers didn't know it then, ⑩but all the world now knows that bats, or rather natural lection working on bats, had perfected the system tens of millions of years earlier, and their 'radar' achieves feats of detection and navigation that w
ould strike an engineer dumb with admiration. ⑪It is technically incorrect to talk about bat 'radar', since they do not u radio waves. It is sonar. ⑫But the underlying mathematical theories of radar and sonar are very similar, and much of our scientific understanding of the details of what bats are doing has come from applying radar theory to them. The American ⑬zoologist Donald Griffin, who was largely responsible for the discovery of sonar in bats, coined the term 'echolocation' to cover both sonar and radar, whether ud by animals or by human instruments.美丽教师
