问答题 (46)The climatic phenomenon that is being blamed for floods, hurricanes and early snowstorms also deserves credit for encouraging plant growth and helping to control the pollutant linked to global warming, a new study shows. E1 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. (47)The new study shows that natural weather events，such as the brief warming caused by E1 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. (48)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 E1 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 E1 Nino, and this leads to increased plant growth, " said Schimel. (49)However, he said, it is not clear whether the warming by E1 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 E1 Nino warming: CO2 atmosphere levels first decline and later increase. (50) " 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. /
【答案解析】[解析] 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被放在了句子末尾，但译成中文时应按照汉语的习惯，把主句放到宾语从句之前；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在这里是“称赞，表扬”的意思。
【答案解析】[解析] 句子的框架是The new study shows that natural weather events…，have a much more…effect 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“影响要比我们先前认为的火得多”；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。
【答案解析】[解析] 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，主语从句中的介词短语in the built-up of CO2中built-up的意思是“增长，积聚”；词组over the long haul是“从长远来看”之意。
【答案解析】[解析] 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一个由that引导的宾语从句，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have…to do with的意思是“和…有关系”。