In the 1980s, scientists around the world began to notice something strange: Frogs were disappearing. More recent research has shown that many kinds of amphibians are declining or have become extinct. They have been around for a long time - over 350 million years. Why are they dying out now? The most serious aspect of amphibian loss, however, goes beyond the amphibians themselves. Scientists are beginning to think about what amphibian decline means for the planet as a whole. If the earth is becoming unlivable for amphibians, is it also becoming unlivable for other kinds of animals and human beings as well? There are a number of other factors in amphibian decline. Pollution is one of them. In many industrial areas, air pollution has poisoned the rain, which then falls on ponds and kills the frogs and toads that live there. In farming areas, the heavy use of chemicals on crops has also killed off amphibians. Another factor is that air pollution has led to increased levels of ultraviolet light. This endangers amphibians, which seem to be especially sensitive to UV light. And finally, scientists have discovered a new disease that seems to be killing many species of amphibians in different parts of the world. 36 Losing amphibians means losing B knowledge about air and water pollution. D an opportunity to detect poisonous gases. A in any stream they can find, C only on sand. 38 The arroyo toad is disappearing because B it is losing its habitat. D it cant bear the cold of winter. A poisonous gases. C water leakage. 40 Scientists think that the decline of amphibians could B cause a decline in other kinds of animals. D be a good sign for human beings.
2016秋人教版英语九年级Unit 2《I think that mooncakes are delicious!》课时学案打包下载(5份)
2016秋人教版英语九年级Unit 5《What are the shirts made of?》课时教案打包下载(3份)
2016秋人教版英语九年级Unit 12《Life is full of the unexpected》课时教案打包下载(4份)
2016秋人教版英语九年级Unit 3《Could you please tell me where the restrooms are》word全单元学案
2016秋人教版英语九年级Unit 12《Life is full of the unexpected》英文版教案打包下载(5份)
2016秋人教版英语九年级Unit 5《What are the shirts made of》课时学案打包下载(3份)
2016秋人教版英语九年级Unit 11《Sad movies make me cry》课时教案打包下载(3份)
2016秋人教版英语九年级Unit 4《I used to be afraid of the dark》课时学案打包下载(4份)
2016秋人教版英语九年级Unit 4《I used to be afraid of the dark》英文版教案打包下载(5份)
2016秋人教版英语九年级Unit 7《Teenagers should be allowed to choose their own clothes》课时学案打包下载(2份)
2016秋人教版英语九年级Unit 8《It must belong to Carla》课时学案打包下载(5份)
2016秋人教版英语九年级Unit 8《It must belong to Carla》英文版教案打包下载(5份)
2016秋人教版英语九年级Unit 7《Teenagers should be allowed to choose their own clothes》课时教案打包下载(2份)
2016秋人教版英语九年级Unit 6《When was it invented》课时教案打包下载(4份)
2016秋人教版英语九年级Unit 2《I think mooncakes are delicious》word全单元学案
2016秋人教版英语九年级Unit 7《Teenagers should be allowed to choose their own clothes.》word全单元教案
2016秋人教版英语九年级Unit 3《Could you please tell me where the restrooms are》英文版教案打包下载(5份)
新目标九年级Unit 8教案1-6
2016秋人教版英语九年级Unit 3《Could you please tell me where the restrooms are》课时教案打包下载(4份)
2016秋人教版英语九年级Unit 4《I used to be afraid of the dark》word全单元教案
2016秋人教版英语九年级Unit 8《It must belong to Carla.》word全单元教案
2016秋人教版英语九年级Unit 9《I like music that I can dance to.》word全单元教案
2016秋人教版英语九年级Unit 8《It must belong to Carla》课时教案打包下载(5份)
2016秋人教版英语九年级Unit 7《Teenagers should be allowed to choose their own clothes》word全单元学案
2016秋人教版英语九年级Unit 13《We’re trying to save the earth》word全单元教案
2016秋人教版英语九年级Unit 8《It must belong to Carla》word全单元学案
2016秋人教版英语九年级Unit 6《When was it invented》word全单元学案
2016秋人教版英语九年级Unit 6《When was it invented》英文版教案打包下载(5份)
2016秋人教版英语九年级Unit 14《 I remember meeting all of you in Grade 7.》word全单元学案
2016秋人教版英语九年级Unit 5《What are the shirts made of》英文版教案打包下载(5份)
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