Question

Against the supposition that forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.

This finding suggests that taking steps to prevent northern forest fires to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over the next several centuries as a result of a longer fire season. Sunlight taken in by the earth tends to cause warming, while heat mirrored back into space tends to cause cooling.

This is the first study to analyze all aspects of how northern fires influence climate. Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.

Scientists found that right after the fire, large amounts of greenhouse gases entered the atmosphere and caused warming. Ozone（臭氧） levels increased, and ash from the fire fell on far-off sea ice, darkening the surface and causing more radiation from the sun to be taken in. The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.

“We need to find out all possible ways to reduce the growth of greenhouse gases in the atmosphere.” Scientists tracked the change in the amount of radiation entering and leaving the climate system as a result of the fire, and found a measurement closely related to the global air temperature. Typically, fire in northern regions occurs in the same area every 80 to 150 years. Scientists, however, found that when fire occurs more frequently, more radiation is lost from the earth and cooling results. Specifically, they determined when fire returns 20 years earlier than predicted, 0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space. The net effect is cooling. Watts are used to measure the rate at which energy is gained or lost from the earth.

1.．According to the new findings, taking steps to prevent northern forest fires may __________.

A．result in a warming climate

B．cause the forest fires to occur more frequently

C．lead to a longer fire season

D．protect the forests and the environment there

2.．The following are all the immediate effects after a forest fire EXCEPT __________.

A．large amounts of greenhouse gases enter the atmosphere

B．the levels of ozone which is a type of oxygen increase

C．snow on the ground mirrors more sunlight back into space

D．ashes from the fire fall on the ice surface and take in more radiation from the sun

3.．Earlier studies about northern forest fires __________.

A．analyze all aspects of how northern fires influence climate

B．indicate that forest fires will pollute the atmosphere

C．suggest that people should take measures to protect environment

D．suggest that the fires will speed up climate warming

4.．The underlined phrase “soak up” in the last paragraph most probably means __________.

A．released

B．absorbed

C．created

D．distributed

5.．From the passage we can draw a conclusion that forest fires in Alaska, Canada and Siberia may ____.

A．warm the climate as the supposition goes

B．allow more snow to reflect more sunlight into space and thus cool the climate

C．destroy large areas of forests and pollute the far-off sea ice

D．help to gain more energy rather than release more energy

 

Answer 1

【答案】

1.A

2.C

3.D

4.B

5.B

【解析】

試題分析：

1..A 細節題。根據第二段1,2行This finding suggests that taking steps to prevent northern forest fires to limit the release of greenhouse gases may warm the climate in northern regions說明這樣的措施最終導致了北部地區的氣候變暖。故A正確。

2..C 推理題。根據第四段后三行The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.說明地上的雪反射陽光這是大火的間接的影響，是在第二年春天的時候發生的事情，并不是immediate effects。故C符合要求。

3.D 細節題。根據第三段2,3行Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.說明Ｄ正確。

4.B 推理題。根據本句0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space.說明該詞與send back該詞相反的意思，故應該指吸收，因為send back指反射。故B正確。

5.B 細節題。根據文章第一段第二行scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.說明從這個研究中得到的結論是B項。

考點：考查科普類短文閱讀

點評：文章主要講述了發生在阿拉斯加，加拿大和西伯利亞的北部大火對當地的氣候所產生的影響，大火過后，樹木都被燒沒有了，會讓更多的雪反射陽光進太空反而是讓溫度變低。本文的障礙在于詞匯方面，考查了細節題和推理題，要求考生在審題時特別當心關鍵的信息詞和各段所持的觀點，結合題目的而要求做出推理判斷。