练习和答案

　　练习

　　（61）The climatic phenomenon that is being blamed for floods，hurricanes and early snowstorms also deserves credit encouraging plant growth and helping to control the pollutant linked to global warming，a new study shows.

　　El Nino_the periodic warming of eastern Pacific Ocean waters_causes a burst of plant growth throughout the world，and this removes carbon dioxide from the atmosphere，researchers have found.

　　（62）The new study shows that natural weather events，such as the brief warming caused by El Nino，have a much more dramatic effect than previously believed on how much carbon dioxide is absorbed by plants and how much of the gas is expelled by the soil.

　　Atmospheric carbon dioxide，or CO2 ，has been increasing steadily for decades.This is thought to be caused by an expanded use of fossil fuels and by toppling of tropical forests.Scientists have linked the CO2 rise to global warming，a phenomenon known as the greenhouse effect.（63）Alarmed，nations of the world now are drawing up new conservation policies to reduce fossil fuel burning，in hopes of reducing greenhouse gases in the atmosphere.

　　But David Schimel of the National Center for Atmospheric Research，a co_author of the new study，says that before determining how much to reduce fossil fuel burning we should consider the effects of natural climate variations on the ability of plants to absorb CO2 .

　　Schimel said satellite measurements of CO2 ，plant growth and temperature show that natural warming events such as El Nino at first cause more CO2 to be released into the atmosphere，probably as the result of accelerated decay of dead plant matter in the soil.But later，within two years，there is an explosion of growth in forests and grasslands，which means plants suck more carbon dioxide out of the atmosphere.

　　“We think that there is a delayed response in vegetation and soil to the warming effects of such phenomena as El Nino，and this leads to increased plant growth，”said Schimel.

　　（64）However，he said，it is not clear whether the warming by El Nino causes a net decrease in the buildup of CO2 over the long haul.“We don’t really know that yet，”said Schimel.What the study does show，however，is that the rise and fall of CO2 in the atmosphere is strongly influenced by natural changes in global temperature，said B.H.Braswell of the University of New Hampshire，another co_author of the study.Braswell said that in years when the global weather is cooler than normal，there is a decrease in both the decay of dead plants and in new plant growth.This causes an effect that is the opposite of El Nino warming:CO2 atmosphere levels first decline and later increase.

　　（65）“I think we have demonstrated that the ecosystem has a lot more to do with climate change than was previously believed，”said Braswell，“Focusing on the role of human activity in climate change is important，but manmade factors are not the only factors.”

　　答案

　　文章大意: 众所周知，厄尔尼诺常常给人类带来灾难性的破坏，令人谈虎色变，但是它究竟有没有好的一面呢?本文就这一问题展开讨论。文章开门见山告诉我们厄尔尼诺能带来好的影响:它促进植物的生长并有助于控制与全球转暖有关的污染物质。提出这一主题之

　　后，作者通过分析厄尔尼诺、植物和二氧化碳三者的关系进行进一步阐述。

　　（61） 结构分析: 句子的框架是The climatic phenomenon that is…also deserves credit for…，a new study shows。因为宾语从句太长，为了保持句子的平衡，主句a new study shows被放在句子末尾，但按照汉语的习惯，译成中文时，应把它提前到宾语从句之前;宾语从句中又包含了that引导的定语从句that is being…and early snowstorms修饰先行词the climatic phenomenon;在原因状语for encouraging plant growth and…linked to global warming中，过去分词短语linked to global warming作the pollutant的后置定语。credit这里是“称赞，表扬”的意思。

　　参考译文: 一项新的研究表明，被认为应对造成洪涝、飓风和暴风雪等提前发生负责任的那种气候现象也有值得称赞的一面，因为它促进植物的生长，并有助于控制与全球转暖有关的污染物质。

　　（62） 结构分析: 句子的框架是The new study shows that natural weather events，…，have a much more…than…on…。句中that引导了宾语从句，从句中have a much more dramatic effect than previously believed里包含了more…than…的结构，可译成“比我们以前认为的要大得多的影响”;在介词结构on how much carbon…and how much of…中，介词on后面接了两个并列的由how much引导的宾语从句。词组have an effect on是“对…有影响，有效果”之意。

　　参考译文: 该项新的研究表明，像“厄尔尼诺”现象引起的短暂升温这种自然气候活

　　动，对植物吸收多少二氧化碳，土壤中释放出多少二氧化碳都有着比我们先前认为的要大得

　　多的影响。

　　（63） 结构分析: 句子的框架是Alarmed，nations…are drawing up…policies to reduce…，in hope of…。过去分词alarmed位于句首作状语，其逻辑主语是nations。动词不定式短语to reduce fossil_fuel burning在句中作目的状语，而介词结构in hope of…也是状语，in hope of的意思是“希望”。

　　参考译文: 惊恐之余，世界各国目前正在制定新的保护政策以减少矿物燃料的燃烧，希望能减少大气中导致“温室效应”的各种气体的含量。

　　（64） 结构分析: 句子的框架是However，he said，it is not clear whether the warming…causes…。句中he said是插入语，it is not clear…是主句。it是形式主语，真正的主语是whether引导的主语从句，主语从句中的介词词组in the built_up of CO2 中的built_up的意思是“增长，积聚”，词组over the long haul是“从长远看”之意。

　　参考译文: 然而，从长远来看，“厄尔尼诺”现象造成的气候变暖是否会引起二氧化碳积聚量的绝对下降，这一点还不清楚。

　　（65） 结构分析: 句子的框架是I think we have demonstrated that…。I think后面紧跟了宾语从句we have demonstrated that…，而宾语从句中又包含了that引导的宾语从句作have demonstrated的宾语，这个宾语从句中又有more…than…结构，than引导了比较状语从句，其中，词组have…to do with的意思是“和…有关系”。

　　参考译文: 我认为我们已经证明了这一点，即生态系统与气候变化之间的关系比我们以前认为的要密切得多。