PEOPLE， like most animals， are naturally lazy. So the ascent of mankind is something of a mystery. Humans who make their livings hunting and gathering in the traditional way do not have to put much effort into it. Farmers who rely on rain to water their crops work significantly harder， and lead shorter and unhealthier lives. But the real back-breaking， health-destroying labour is that carried out by farmers who use irrigation. Yet it was the invention of irrigation， at first sight so detrimental to its practitioners， that actually produced a sufficient surplus to feed the priests， politicians， scholars， artists and so on whose activities are collectively thought of as “civilisation”。

In the past 10，000 yeas， the world‘s climate has become temporarily colder and drier on several occasions. The first of these， known as the Younger Dryads， after a tundra-loving plant that thriced during it， occurred at the same time as the beginning of agriculture in northern Mesopotamis. It is widely believed that this was nor a coincidence. The drying and cooling of the YOUNGER Dryads adversely affected the food supply of hunter-gatherers. That would have created an incentive for agriculture to spread once some bright spark invented it.

Why farmers then moved on to irrigation is， however， far from clear. But Harvey Weiss， of Yale University， think she knows. Dr. Weiss observes that the development of irrigation coincides with a second cool， dry period， some 8，200 years ago. His analysis of rainfall patterns in the area suggests that rainfall in agriculture‘s upper-Mesopotamian heartland would， at this time， have falllen below the level needed to sustain farming reliably. Farmers would thus have been forced out of the area in search of other opportunities.

Once again， an innovative spark was required. But it clearly occurred to some of these displaced farmers that the slow-moving waters of the lower Tigris and Euphrates， near sea level， could be diverted using canals and used to water crops， and the rest， as the clich has it， is history.

So climate change helped to intensify agriculture， and thus start civilization. But an equally intriguing idea is that the spread of agriculture caused climate change. In this case， the presumed criminal is forest clearance. Most of the land cultivated by early farmers in the Middle East would have been forested. When the trees that grew there were cleared， the carbon they contained ended up in the atmosphere as carbon dioxide. Moreover， one form of farming—the cultivation of rice in waterlongged fields—generates methane， in large quantities. Willianm Ruddiman， of the University of Virginia， explained that， in combination， these two phenomena had warmed the atmosphere prior to the start of the industrial era. As environmentalists are wont to observe， mankind is part of nature. These studies show just how intimate the relationship is.

1. The invention of irrigation is meaningful because it could help to

[A] alleviate farmers‘ workload

[B] increase agricultural production.

[C] make planting much easier

[D] get rid of human laziness.

2. According to Dr. Weiss， the second cool and dry period eventually

[A] changed the growing season.

[B] spurred the use of canals.

[C] forced the farmers to desert agriculture.

[D] led to declining populations.

3. From the first four paragraphs， we can infer that the dawn of civilization

[A] was accompanied by hardships of human existence.

[B] is a mystery as yet unknown to mankind.

[C] can be attributed to the innovative sparks of ancestors.

[D] was recorded by history books ending at that time.

4. Which of the following tends to warm the climate?

[A] To develop the irrigation system.

[B] To promote organic agriculture.

[C] To revert to hunting and gathering

[D] To turn farmland back into forest.

5. the text is mainly about

[A] the relationship between climate change and civilization.

[B] the history of global climate change.

[C] the interaction between nature and human society.

[D]the impact of the spread of agriculture.

答案与解析

1. B 细节题。本题的问题是“灌溉的发明具有重要意义，因为它可能有助于”。题干中的“the invention of irrigation”出自文章第一段最后一句话中，表明本题与第一段有关。第一段提到，正是乍一看对其实践者如此有害的灌溉发明才真正生产出足够的剩余产品养活了牧师、学者、艺术家等等。这说明，原因是它增加了农业产量。[B]“提高农业产量”与此意符合，为正确答案。[A]“减轻农民的劳动强度”和[C]“使种植容易得多”与该段第五句话的意思相反;[D]“消除人类的懒惰”是针对该段第一句话设置的干扰项，但文中的信息并不能说明灌溉的发明消除了人类的懒惰，他们只是为了生计而勤劳，所以D与文意不符。

2. B 细节题。本题的问题是“根据韦斯博士的观点，第二个寒冷、干燥的时期最终 ”。题干中的“Dr.Weiss”和“the second cool and dry period”出自文章第三段第二、三句话中，表明本题与第三段有关。第三段介绍了韦斯博士的观点——灌溉的发展时期与大约8，200年前的第二个寒冷、干燥时期时间吻合，接着提到了他的分析，指出，当时美索不达米亚北部农业中心地带的降雨可能减少，低于维持农业稳步发展的水平，第四段接着提到农民想到利用运河灌溉农作物的问题。这说明，韦斯博士认为，第二个寒冷、干燥的时期可能促进了运河的发展。[B]“促进了运河的利用”与此意符合，为正确答案。[A] “改变了生长季节”和[D]“导致人口减少”属于无中生有;[C]“迫使农民放弃农业”是针对第三段最后一句话设置的干扰项，文中说的是被迫离开降雨减少的地区，不是放弃农业，所以C与文意不符。

3. A 推论题。本题的问题是“根据前面四段，我们可以推知，文明的起源 ”。文章第一段首先提到了灌溉的发明的意义，随后三段介绍了气候的变化导致农民生活艰难，也促进了灌溉的发展，最后一段指出，气候变化有助于强化农业的发展，进而开创文明。由此可知。文明的起源伴随的是人类生存的艰难。[A]“伴随着人类生存的艰难困苦”与此意符合，为正确答案。[B]“是人类还不知道的一个秘密”是针对第一段第二句话和第三段第一句话设置的干扰项，与文意不符;文中的信息表明，是气候的变化导致了人们生存困难，从而激发了创造灵感，说明气候的变化是关键，所以[C]“可能归因于祖先的创造灵感”与文意不符;[D]“根据历史书记载于那个时候结束”是针对第四段最后一句话设置的干扰项，明显与文意不符。

4. B 细节题。本题的问题是“下面哪项往往导致气候变暖?”最后一段解释了大气升温的原因——早期的农民砍伐树木可能导致树木所含的碳转化成二氧化碳进入大气，在水田里种植水稻产生了大量的甲烷，这两种现象共同导致了工业时代之前的大气升温。这说明，发展农业可能导致气候变暖。[B]“发展有机农业”与此意符合，为正确答案。文中的信息并没有表明灌溉与气候变暖有关系，所以[A]“发展灌溉系统”不对;[C]“回归狩猎和采摘生活”和[D]“退耕还林”是在保护树木，不会导致气候变暖，所以不对。

5. A 主旨题。本题的问题是“本文主要是关于 ”。文章第一段提到，灌溉的发明促进了文明的发展，随后的段落分析指出，灌溉的发明是气候变化的结果，最后一段总结到，气候变化有助于强化农业的发展，进而开创文明。这说明，本文主要讲的是气候变化与文明的发展之间的关系。[A]“气候变化与文明之间的关系”是对本文内容的恰当概括，可以表达本文的主题，为正确答案。本文只是在第二、三段提到了全球气候发生的变化，而这是为了说明气候变化导致灌溉的发展所举的例子，不是本文讨论的重点，所以[B]“全球气候变化的历史”不能表达本文的主题;[C]“自然界和人类社会的交互作用”范围太广，不能表达本文的主题;[D]“农业发展产生的影响”只是最后一段的内容，不能表达本文的主题。