注釋：
1. the Max Planck Institute for Nuclear Physics in Heldelberg, Germany：馬克思·普朗克核物理研究所，位于德國海德堡。海德堡系德國西南部城市，在巴登－符騰堡州的內(nèi)卡河畔。海德堡大學(xué)是德國歷史最悠久的大學(xué)。
2. microbe：細(xì)菌，意義同 bacterium（bacteria的單數(shù)形式），但 microbe 不用作專門術(shù)語。
3. St. Paul：圣保羅，美國明尼蘇達(dá)州首府。
練習(xí)：
1. What was scientists’ understanding of methane?
A) It was produced from plants.
B) It was not a greenhouse gas.
C) It was produced in oxygen-free environments.
D) It traps more heat than any other greenhouse gas.
2. To test whether plants are a source of methane, the scientists created
A) a oxygen-free environment.
B) an environment with the same concentration of oxygen as the Earth has.
C) a carbon dioxide-free environment.
D) an environment filled with the greenhouse gas
3 Which statement is true of the methane emissions of plants in the experiment?
A) The lower the temperature, the higher the amount of methane emissions.
B) Living plants release less methane than dried plants at the same temperature.
C) When exposed to sunlight, plants stop releasing methane.
D) The higher the temperature, the greater the amount of methane emissions.
4. What of the following about methane is Not mentioned in the passage ?
A) Plants growing in soil release methane.
B) Plants growing in water release methane.
C) Soil microbes consume methane.
D) Microbes in plants produce methane.
5. What is the beneficial point of some microbes consuming plant-produced methane?
A) Methane becomes less poisonous.
B) methane is turned into a fertilizer.
C) Less methane reaches the atmosphere.
D) Air becomes cleaner..
答案與題解：
1. C 短文的第一和第二段都講到，科學(xué)家過去曾經(jīng)認(rèn)為，沼氣必須在無氧的環(huán)境中才能產(chǎn)生。注意，作者用的是過去式：Most scientists assumed that …， They had assumed that…。
2. B 第三段第一句說，科學(xué)家使用密封的房間來做實驗，房間里氧氣的濃度與地球大氣中的氧氣濃度相仿。所以 B 句符合原文的意思，其它三個選擇則不符合原文內(nèi)容。
3. D 根據(jù)第四和第五段的內(nèi)容，只有 D 是正確的說法。溫度越高沼氣的釋放量越高，有生命的植物釋放的沼氣遠(yuǎn)大于干植物的釋放量，在陽光下，它們的沼氣釋放量是正常情況的三倍。
4. D 最后兩段告訴我們，無論在土壤中還是在水中生長的植物都能釋放沼氣，土壤中的微生物消耗沼氣，使沼氣不至于進(jìn)入空氣。所以A、B、C 的內(nèi)容均符合短文最后兩段中作者的意思。D 的內(nèi)容短文中沒有提到。
5. C 最后一段的第二句可以找到本題的答案。
1. the Max Planck Institute for Nuclear Physics in Heldelberg, Germany：馬克思·普朗克核物理研究所，位于德國海德堡。海德堡系德國西南部城市，在巴登－符騰堡州的內(nèi)卡河畔。海德堡大學(xué)是德國歷史最悠久的大學(xué)。
2. microbe：細(xì)菌，意義同 bacterium（bacteria的單數(shù)形式），但 microbe 不用作專門術(shù)語。
3. St. Paul：圣保羅，美國明尼蘇達(dá)州首府。
練習(xí)：
1. What was scientists’ understanding of methane?
A) It was produced from plants.
B) It was not a greenhouse gas.
C) It was produced in oxygen-free environments.
D) It traps more heat than any other greenhouse gas.
2. To test whether plants are a source of methane, the scientists created
A) a oxygen-free environment.
B) an environment with the same concentration of oxygen as the Earth has.
C) a carbon dioxide-free environment.
D) an environment filled with the greenhouse gas
3 Which statement is true of the methane emissions of plants in the experiment?
A) The lower the temperature, the higher the amount of methane emissions.
B) Living plants release less methane than dried plants at the same temperature.
C) When exposed to sunlight, plants stop releasing methane.
D) The higher the temperature, the greater the amount of methane emissions.
4. What of the following about methane is Not mentioned in the passage ?
A) Plants growing in soil release methane.
B) Plants growing in water release methane.
C) Soil microbes consume methane.
D) Microbes in plants produce methane.
5. What is the beneficial point of some microbes consuming plant-produced methane?
A) Methane becomes less poisonous.
B) methane is turned into a fertilizer.
C) Less methane reaches the atmosphere.
D) Air becomes cleaner..
答案與題解：
1. C 短文的第一和第二段都講到，科學(xué)家過去曾經(jīng)認(rèn)為，沼氣必須在無氧的環(huán)境中才能產(chǎn)生。注意，作者用的是過去式：Most scientists assumed that …， They had assumed that…。
2. B 第三段第一句說，科學(xué)家使用密封的房間來做實驗，房間里氧氣的濃度與地球大氣中的氧氣濃度相仿。所以 B 句符合原文的意思，其它三個選擇則不符合原文內(nèi)容。
3. D 根據(jù)第四和第五段的內(nèi)容，只有 D 是正確的說法。溫度越高沼氣的釋放量越高，有生命的植物釋放的沼氣遠(yuǎn)大于干植物的釋放量，在陽光下，它們的沼氣釋放量是正常情況的三倍。
4. D 最后兩段告訴我們，無論在土壤中還是在水中生長的植物都能釋放沼氣，土壤中的微生物消耗沼氣，使沼氣不至于進(jìn)入空氣。所以A、B、C 的內(nèi)容均符合短文最后兩段中作者的意思。D 的內(nèi)容短文中沒有提到。
5. C 最后一段的第二句可以找到本題的答案。