注释：
1. the Max Planck Institute for Nuclear Physics in Heldelberg, Germany：马克思•普朗克核物理研究所，位于德国海德堡。海德堡系德国西南部城市，在巴登－符腾堡州的内卡河畔。海德堡大学是德国历史最悠久的大学。
2. microbe：细菌，意义同 bacterium（bacteria的单数形式），但 microbe 不用作专门术语。
3. St. Paul：圣保罗，美国明尼苏达州首府。
练习：
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) an 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。
责任编辑：虫虫
