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  3. 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 area

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 area

admin2014-12-31  32
问题     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(两栖动物)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(鸭嘴兽)frog. Like the well-known Australian mammal it was named after, it exhibited some very strange behavior; 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.
What is NOT true about the platypus frog?
选项 A、It became extinct by 1991.
B、It is not the only frog species that vanished in Australia.
C、It gives birth to its baby frogs just like human beings.
D、It is not a kind of mammals.
答案C
解析 细节题。根据文章第二段，它1981年被发现，不到十年就完全消失了，故1991年它就完全灭绝了，A正确。文章后来提到有不少于8种其他物种灭绝了，故B正确。文章对于它繁殖的内容这样说，“instead of giving birth to tadpoles in thewater，it raised its young within its stomach．The baby frogs were actually bom from outof their mother’s mouth”，即在腹中怀子，从嘴中生产，和人并不一样，故C错误。它只是因为繁殖方式和鸭嘴兽相同而被叫作platypus frog，但是它是青蛙，不是哺乳动物。故D错误。
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