Question

The planet is getting greener, and we are responsible. Carbon dioxide generated by human activities is promoting photosynthesis (光合作用) and causing a beneficial greening of the Earth’s surface.

For the first time, researchers claim to have shown that the increase in plant cover is due to this “CO2 fertilisation (肥沃化) effect” rather than other causes. However, it remains unclear whether the effect can reduce any negative effects of global warming, such as the spread of deserts.

To home in on the effect of CO2, Randall Donohue of Australia’s national research institute, the CSIRO in Canberra, monitored vegetation (植被) at the edges of deserts in Australia, southern Africa, the US Southwest, North Africa, the Middle East and central Asia. These are regions where there is plenty of warmth and sunlight, but only just enough rainfall for vegetation to grow, so any change in plant cover must be the result of a change in rainfall patterns or CO2 levels, or both.

If CO2 levels were constant, then the amount of vegetation per unit of rainfall ought to be constant, too. However, the team found that this figure rose by 11 per cent in these areas between 1982 and 2010, mirroring the rise in CO2 emissions (排放). Donohue says this lends strong support to the idea that CO2 fertilization drove the greening.

The extra plant growth could have knock-on effects on climate, Donohue says, by increasing rainfall, affecting river flows and changing the likelihood of wildfires. It will also absorb more CO2 from the air, potentially damping down (抑制) global warming but also limiting the CO2 fertilization effect itself.

Donohue cannot yet say to what extent CO2 fertilisation will affect vegetation in the coming decades. But if it proves to be significant, the future may be much greener.

1.According to the author, the increase in plant cover _____.

A. will speed up global warming

B. results from human activities

C. will stop the spread of deserts

D. promotes the CO2 fertilization effect

2.What does the underlined phrase “To home in on” in Para 3 probably mean?

A. To hold back. B. To cut down.

C. To improve. D. To observe.

3. The amount of vegetation in those monitored areas rose with _____.

A. the rise in CO2 emissions B. annual rainfall

C. the temperatures around D. the amount of sunlight

4.What’s the best title of the text?

A. More rainfall, less CO2 emission

B. How to deal with carbon emissions

C. Positive effects of global warming

D. CO2 emission making Earth greener

Answer 1

1.B

2.D

3.A

4.D

【解析】本文是一篇說明文。我們生活的地球的植被越來越茂盛。研究人員研究發(fā)現(xiàn)，這些植物越來越綠的原因不是因?yàn)閯e的，正是因?yàn)槎�氧化碳肥沃化效�?yīng)。

1. Carbon dioxide generated by human activities is promoting photosynthesis (光合作用) and causing a beneficial greening of the Earth’s surface.由人類活動產(chǎn)生出的二氧化碳正在促進(jìn)光合作用，使得地球表面綠化。故選B

2. home in on the effect of CO2, …monitored vegetation (植被) at the edges of deserts in Australia, southern Africa, the US Southwest, North Africa, the Middle East and central Asia.監(jiān)管澳大利亞、南非、北美西南部、北非、中東和中亞的沙漠邊緣的植被。我們根據(jù)該句子結(jié)構(gòu)可知道，劃線句是一個動詞不定式做目的狀語，句子的謂語部分是對達(dá)成目的具體的方法的描述。由monitored可知意思為監(jiān)管、監(jiān)控。故選D

3. However, the team found that this figure rose by 11 per cent in these areas between 1982 and 2010, mirroring the rise in CO2 emissions (排放).然而，這個團(tuán)隊(duì)發(fā)現(xiàn)在1982年到2010年這些地區(qū)的反應(yīng)二氧化碳排放的數(shù)據(jù)上升了11個百分點(diǎn)。故選A

4.

考點(diǎn)：考察說明文閱讀。