Question

Directions: After reading the passage below, fill in the blanks to make the passage coherent and grammatically correct. For the blanks with a given word, fill in each blank with the proper form of the given word; for the other blanks, use one word that best fits each blank.

Over-dried Earth

The south-west of the United States, together with some parts of Mexico across the Rio Grande, is one of the driest parts of the North American continent. But, over the past two decades, even that expected dryness 1. (take) to the limit. According to Park Williams, who works at Columbia University’s Lamont-Doherty Earth Observatory, the current lack of rainfall in the area constitutes a megadrought of a severity 2.(see) on only four other occasions in the past 1,200 years.

Dr Williams studies the annual growth rings of 1,586 ancient trees, in order to reconstruct soil-moisture patterns going back to 800 A.D. During warm, wet years trees grow fast, producing wide rings. During cold, dry 3. they grow more slowly, producing narrow rings. During a drought, a tree 4. not grow much at all.

5.they describe in this week’s Science, the team identified dozens of droughts over the centuries in question. But four stood out. They then took the average soil-moisture value for the current drought and compared it with sequential（连续的） 19-year averages with the previous four, one of them 6.(last) nearly a century. This showed that the region is already drier than it was during the first three of the previous megadroughts, and is equivalent to the event of 1575-1603.

In a world 7. human actions are driving temperatures up, Dr Parker and his colleagues wondered how much people are 8.(blame) for this state of affairs. To estimate that, they turned to climate modelling.

Climate models are able to re-run the past with and 9. the warming effects of human activity, offering a way to compare what actually happened with what might have done. In their simulated world in which anthropogenic（人类起源的） emissions had not increased the greenhouse-gas effect, the team found that a drought did indeed still influence the western reaches of North America during the first two decades of the 21st century. But this imaginary dry spell was considerably 10.(severe) than the real one-ranking 11th rather than 2nd in the period under study (see chart).

Answer

1.has been taken

2.seen

3.ones

4.might /may

5.As

6.lasting

7.where

8.to blame

9.without

10.less severe

【解析】

本文是说明文。文章以美国和墨西哥的部分地区为例，讲述了科学家对过度干燥的地球的研究。研究表明，人类活动对于对球变得过热起到了推动的作用。

1.考查时态和语态。句意：但是，在过去的二十年中，预期的干旱也已达到极限了。由时间状语over the past two decades可知，句子使用现在完成时，主语dryness承受动词take的动作，谓语动词使用被动语态，并且主语为不可数名词，谓语动词用单数形式。故填has been taken。

2.考查过去分词。句意：根据哥伦比亚大学拉蒙特-多尔蒂地球观测站工作的帕克·威廉姆斯的说法，该地区目前的降雨不足造成了特大干旱，其严重程度在过去的1200年中仅在其他四个场合出现过。megadrought of a severity承受动词see的动作，使用过去分词作后置定语。故填seen。

3.考查不定代词。句意：在寒冷干燥的季节，它们生长较慢，产生狭窄的年轮。为避免重复，使用ones代替前面的复数名词years。故填ones。

4.考查情态动词。句意：在干旱期间，树可能不会长很多。根据语境，此处填入情态动词表示推测，意为“可能”。故填might/may。

5.考查定语从句的引导词。句意：正如他们在本周的《科学》杂志上描述的那样，研究小组确定了几个世纪以来发生的数十次干旱。分析句子结构可知，此处需填入连词as引导定语从句，并指代逗号后面的句子，意为“正如”。故填As。

6.考查现在分词。句意：然后，他们获取了当前干旱的平均土壤水分值，并将其与连续19年的平均值进行了比较，并将其与前四个平均值进行比较，其中一个数值持续了近一个世纪。分析句子结构可知，逗号后面的last的作为动词使用，应填入非谓语动词的形式，one of them发出last的动作，因此应使用现在分词的形式。故填lasting。

7.考查定语从句的引导词。句意：在这个人类举动加剧气温的世界中，帕克博士和他的同事们想知道人类应该为这种状况负多少责任。分析句子结构可知，此处需填入连词引导定语从句，先行词是world，它在从句中作地点状语。故填where。

8.考查固定短语。句意：在这个人类举动加剧气温的世界中，帕克博士和他的同事们想知道人类应该为这种状况负多少责任。be to blame for：为……应该受到责备，为……承担责任，这是固定用法。故填to blame。

9.考查介词。句意：气候模型能够在有和没有人类活动带来变暖影响的情况下重现过去，从而提供一种比较实际发生的事情和可能做过的事情的方式。由下文的“anthropogenic emissions had not increased the greenhouse-gas effect（人为排放并没有增加温室气体的影响）”可知，此处应填入介词with的反义词without，即without the warming effects of human activity（没有人类活动导致的变暖影响），这两部分是同义表达。故填without。

10.考查形容词的比较级。句意：但是，同期的研究发现这种虚构的干旱没有真正的排名第11的干旱严重却比排名第2的严重（参见图表）。由than可知，形容词severe应使用比较级的形式。结合图表信息可知，表示“程度没有那么严重”应使用less+形容词。故填less severe。