Passage FourQuestions 36 to 40 are based on the following passage:

Carbon dioxide makes up less than one percent of the Earth’s atmosphere. But the gas is very important to life on Earth. Scientists are finding that processes involving carbon dioxide affect our climate in ways that are difficult to understand. Last month, a committee of the National Academy of Sciences in Washington released a report. It confirmed that  increased about six-tenths of a degree Celsius¹ in the last one hundred years. The report also confirmed evidence that the level of carbon dioxide is increasing.

The best information about climate in the past comes from tests of ice many kilometers deep in Antarctica and Greenland. The tests show changes in temperature during the past four-hundred-thousand years. These tests show that levels of carbon dioxide today are the highest ever measured. These findings have led scientists to believe that carbon dioxide is a major cause of climate warming.

Carbon dioxide is released into the atmosphere when fuel is burned. Oil, coal and wood are all fuels that release the gas. When biological waste breaks down, it also releases carbon dioxide.
However, plants use carbon dioxide in the process called photosynthesis². This process provides food for almost all life on Earth. Some groups that support burning oil and coal want to increase the amount of carbon dioxide in the atmosphere. They oppose international efforts to control carbon dioxide.

Some scientists believe that forests and trees are able to capture large amounts of carbon dioxide from the air. Some groups even suggest  in carbon dioxide could cause plants to grow faster.

A recent study in North Carolina found that more carbon dioxide in the air could cause trees to grow faster. But the researchers found the effect appears to last for only three years. Another study showed that much of the carbon dioxide that is taken in by trees is released within three years. The study noted³ that leaves release carbon dioxide when they fall from trees and break down in the soil. Plants also naturally release carbon dioxide through the process of respiration⁴.

The natural balance of gases in the atmosphere is a complex scientific issue. The debate over carbon dioxide is only one part of efforts to understand world climate change.

36.Which one is NOT mentioned in this passage that can be the source of carbon dioxide
A) Oil. 　B) Trees.C) Wood.　D) Soil.

37.The committee report of National Academy of Sciences in Washington reveal that____.
A) ice from Antarctica and Greenland is appropriate to show the change
B) carbon dioxide is released mainly from the fuel
C) level of carbon dioxide increases with global temperatures
D) carbon dioxide is helpful for tree growth

38.According to this passage, those people disagree with the control of carbon dioxide because____.
A) they think that carbon is beneficial for plant growth
B) they want to use more fuels that can emit carbon dioxide
C) they think carbon dioxide is not the main reason for global warming
D) they think it will destroy the natural balance of gases in the world

39.The word “issue” in the last paragraph can be replaced as ____.
A) organ　B) topicC) publication　D) result

40.Those studies carried out in North Carolina suggest that ____.
A) trees’ function for absorbing carbon dioxide is limited
B) carbon dioxide is the main cause for global warming
C) leaves falling from trees can emit more oxygen
D) more carbon dioxide is beneficial for trees’ growth for many decades

36.【答案】D。
【译文】在本文中土壤未被提及是二氧化碳的源头。
【试题分析】客观事实题。
【详细解答】可见第四段“Oil, coal and wood are all fuels that release the gas.”倒数第二段“The study noted that leaves release carbon dioxide when they fall from trees and break down in the soil. Plants also naturally release carbon dioxide through the process of respiration.”而土壤未被提及过。

37.【答案】C。
【译文】研究报告表明二氧化碳的浓度随着全球气温升高而增加。
【试题分析】客观事实题。
【详细解答】关键语句:“The tests show changes in temperature during the past four-hundred-thousand years. These tests show that levels of carbon dioxide today are the highest ever measured.”可见C)正确.A)是作实验的原料而不是分析结果.B),D)为下面的内容。

38.【答案】B。
【译文】反对控制二氧化碳的这些人目的在于燃烧更多能燃烧二氧化碳的原料。
【试题分析】事实推理题。
【详细解答】关键语句:“Some groups that support burning oil and coal want to increase the amount of carbon dioxide in the atmosphere. They oppose international efforts to control carbon dioxide.” C), D)在文中没提.而A)而在文中出现在:“Some groups even suggest  in carbon dioxide could cause plants to grow faster.”可见至少不是动机。

39.【答案】B。
【译文】词义判析题。
【试题分析】最后一段的“issue”应指Topic。
【详细解答】根据后面的debate也可以看出这是一个科学论题。A)器官，C)刊物，D)结论，均不符合题意。

40.【答案】A。
【译文】事实分析题。
【试题分析】在北卡罗来那州的试验表明树木对二氧化碳的吸收作用是有限的。
【详细解答】关键语句:“A recent study in North Carolina found that more carbon dioxide in the air could cause trees to grow faster. But the researchers found the effect appears to last for only three years. Another study showed that much of the carbon dioxide that is taken in by trees is released within three years.”而C)应是放出二氧化碳;D)只有三年;B)是本文开头所做的试验。