2013年6月英語六級閱讀理解Setion B2原文答案及點評（滬江網(wǎng)校版）

Part IV Reading Comprehension

Section B-2原文+答案+點評

Section B

Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should decide on the best choice and mark the corresponding letter on Sheet 2 with a single line through the center.

Passage Two

“Usually when we walk through the rain forest we hear a soft sound from all the moist leaves and organic debris on the forest floor,” says ecologist Daniel Nepstad. “Now we increasingly get rustle and crunch. That’s the sound of a dying forest.”

Predictions of the collapse of the tropical rain forests have been around for years. Yet until recently the worst forecasts were almost exclusively linked to direct human activity, such as clear- cutting and burning for pastures or farms. Left alone, it was assumed, the world’s rain forests would not only flourish but might even rescue us from disaster by absorbing the excess carbon dioxide and other planet-warming greenhouse gases. Now it turns out that may be wishful thinking. Some scientists believe that the rise in carbon levels means that the Amazon and other rain forests in Asia and Africa may go from being assets in the battle against rising temperatures to liabilities. Amazon plants, for instance, hold more than 100 billion metric tons of carbon, equal to 15-years of tailpipe and chimney emissions. If the collapse of the rain forests speeds up dramatically, it could eventually release 3.5-5 billion metric tons of carbon into the atmosphere each year making forests the leading source, of greenhouse gases.

Uncommonly severe droughts brought on by global climate change have led to forest-eating wildfires from Australia to Indonesia, but nowhere more acutely than in the Amazon. Some experts say that the rain forest is already at the brink of collapse.

Extreme weather and reckless development are plotting against the rain forest in ways that scientists have never seen. Trees need more water as temperatures rise, but the prolonged droughts have robbed them of moisture, making whole forests easily cleared of trees and turned into farmland. The picture worsens with each round of El Nino, the unusually warm currents in the Pacific Ocean that drive up temperatures and invariably presage (預(yù)示)droughts and fires in the rain forest. Runaway fires pour even more carbon into the air, which increases temperatures, starting the whole vicious cycle all over again.

More than paradise lost, a perishing rain forest could trigger a domino effect sending winds and rains kilometers off course and loading the skies with even greater levels of greenhouse gases—that will be felt far beyond the Amazon basin. In a sense, we are already getting a glimpse of what’s to come. Each burning season in the Amazon, fires deliberately set by frontier settlers and developers hurl up almost half a billion metric tons of carbon a year, placing Brazil among the top five contributors to greenhouse gases in the world.

57. We learn from the first paragraph that _______.

A) dead leaves and tree debris make the same sound

B) trees that are dying usually give out a soft moan

C) organic debris echoes the sounds in a rain forest

D) the sound of a forest signifies its health condition

58. In the second paragraph, the author challenges the view that _______.

A) the collapse of rain forests is caused by direct human interference

B) carbon emissions are the leading cause of current global warming

C) the condition of rain forests has been rapidly deteriorating

D) rain forests should not be converted into pastures or farms

59. The author argues that the rising carbon levels in rain forests may _______.

A) turn them into a major source of greenhouse gases

B) change the weather patterns throughout the world leaves

C) pose a threat to wildlife

D) accelerate their collapse

60. What has made it easier to turn some rain forests into farmland?

A) Rapid rise in carbon levels.

B) Reckless land development.

C) Lack of rainfall resulting from global warming.

D) The unusual warm currents in the Pacific Ocean.

61. What makes Brazil one of the world’s top five contributors to greenhouse gases?

A) The domino effect triggered by the perishing rain forests,

B) Its practice of burning forests for settlement and development,

C) The changed patterns of winds and rains in the Amazon area.

D) Its inability to curb the carbon emissions from industries.

【總評】

本文顛覆了人們根深蒂固的一個觀念，即熱帶雨林能夠吸收大量二氧化碳及其他溫室氣體，從而保護人類免于危害。

該文指出，一些科學(xué)家現(xiàn)認為碳含量的升高意味著熱帶雨林或許會從溫室效應(yīng)的“衛(wèi)士”，轉(zhuǎn)而成為導(dǎo)致氣溫升高的元兇。他們指出亞馬遜森林中的植物本身含有1000公噸的碳，如果熱帶雨林加速瓦解，它們所釋放的二氧化碳將是導(dǎo)致溫室效應(yīng)的主要原因。

短文后幾段還指出極端天氣和毫無節(jié)制的開發(fā)讓科學(xué)家們見到了從未想象的可怕畫面，更糟糕的是，厄爾尼諾的“雪上加霜”會導(dǎo)致惡性循環(huán)。

文章最后指出熱帶雨林的衰變會形成一個多米諾效應(yīng)，最終導(dǎo)致巴西的亞馬遜森林成為世界上導(dǎo)致溫室氣體的五大元兇之一。

【參考答案】：

57. D. the sound of a forest signifies its health condition.

58. A. the collapse of rain forests is caused by direct human interference.

59. A. turn them into a major source of greenhouse gases

60. C. Lack of rainfall resulting from global warming.

61. B. Its practice of burning forests for settlement and development.