閱讀T/F/NG模擬試題(1)
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小編： 136來源：環球教育網 www.ielts.com.cn 2006－3－28
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.日韩美女一区二区三区-久久久精品在线视频-五月天久久久噜噜噜久久-国产免费视屏-影音先锋亚洲资源-大番蕉尹人一线久久-国产高清视频在线观看97-成人春色影视-综合亚洲桃色第一影院-免费看污视频在线观看-久久这里只精品热在线18-黄色一级视频看看-www.桃色-不卡av网-国产亚洲日韩妖曝欧美-成人国产精品一区