17．A．A careful analysis biologically
B．What's globle warming？
C．Solution to the terrifying result
D．Greater danger of extinction
E．Many shocking things found F．A shocking report
76．B
The earth is getting warmer．People burn coal，oil and gas and this produces carbon dioxide，methane and nitrous oxide．These gases，called"greenhouse gases"，prevent the heat of the sun from leaving the earth's upper atmosphere and this makes the earth warmer．
77．F
A few weeks ago a group of scientists produced a report about global warming and the natural world．They wanted to find out if global warming was dangerous for plants and animals．According to what they found，the scientists say that during the next 50years about 25% of land animals and plants will become extinct．More than a million plant and animal species will be extinct by 2050．
78．C
More than 10% of all plants and animals will become extinct．It is too late to save many plants and animals because of the greenhouse gases that are already in the atmosphere．But the scientists say if we control greenhouse gases now，we could save many more plants and animals from extinction．
79．A
The scientists studied some regions of the world with a very rich biology．These regions were Europe，Australia，Central and South America，and South Africa．Their studies showed that species living in mountainous areas had a better chance of survival because they could move uphill，to get cooler．In flat areas，such as deserts，plants and animals would have to move a very long distance to get cooler，so they are in greater danger of extinction．
80．E
The scientists found that half of the 24 species of butterflies they studied in Australia would soon become extinct.60% of the species in the Kruger National Park in South Africa would also die out，and more than 100% of the 300 South Africa plant species they studied would also become extinct．One of the plants in danger of extinction is the national flower of South Africa，the King Protea．They studied 163 tree species in the Cerrado region of Brazil and found that 70 would become extinct．Many of the plants and trees that live in this region live nowhere else in the world．In Mexico，they studied 1，870 species and found that more than 30% of these were in danger of extinction．
分析 本文主要寫了全球變暖的原因，變暖給整個地球的物種造成的巨大危害，人類應(yīng)該控制溫室氣體來挽救地球物種．
解答 76．B 主旨大意題．根據(jù)句子These gases，called"greenhouse gases"，prevent the heat of the sun from leaving the earth's upper atmosphere and this makes the earth warmer．
這些被稱為"溫室氣體"的氣體，阻止太陽的熱量離開地球的上層大氣，使地球變暖．可見這是對全球氣溫變暖進(jìn)行的解釋．所以B選項什么是全球變暖符合段意．
77．F 主旨大意題．從這段的內(nèi)容和第一句話A few weeks ago a group of scientists produced a report about global warming and the natural world．More than a million plant and animal species will be extinct by 2050． 報告的結(jié)果是超過一百萬種動植物將在2050之前滅絕．可知是關(guān)于一個令人吃驚的報告．所以選F．
78．C 主旨大意題．根據(jù)句子 But the scientists say if we control greenhouse gases now，we could save many more plants and animals from extinction．如果控制的溫室氣體就能挽救更多的動植物，可知這段是對可怕結(jié)果的解決辦法．選C
79．A 主旨大意題．從這段的第一句話：The scientists studied some regions of the world with a very rich biology．可知是從生物角度的仔細(xì)分析．選A
80．E 信息提取題．這段里面出現(xiàn)了很多數(shù)據(jù)，例如The scientists found that half of the 24 species of butterflies they studied in Australia would soon become extinct科學(xué)家們發(fā)現(xiàn)，在澳大利亞研究的24種蝴蝶中，有一半很快就會滅絕．以下列舉的數(shù)據(jù)的發(fā)現(xiàn)都是讓人震驚的事情．選E很多令人震驚的發(fā)現(xiàn)符合段意．
點評 本文主題是全球氣溫變暖的情況和一些驚人的事實，主要是找出適當(dāng)?shù)亩温渲黝}，要學(xué)生有很強的歸納能力．
