托福阅读真题+题目+答案+译文：Alaska and Bark Beetles

2015年7月11日托福阅读真题+题目+答案：Alaska and Bark Beetles

1. Over the twentieth century, global temperatures increased by an average of about 0.7 degrees Celsius, but some places have warmed a lot more than this, and other places have warmed less. These temperature increases have been enough to trigger changes in ecosystems all over the world, especially in places where the warming has been the greatest. In some places, the changes have been subtle, perhaps a slight shift in vegetation that only a careful observer would notice. In other cases, small changes in climate have sparked a chain of larger effects, leading to massive changes.

20世纪以来，全球气温平均上升了约0.7摄氏度，但有些地方的气温上升幅度要远远大于这个平均值，其他地方的气温上升幅度相对较小。这些气温上升已经足以引发世界各地的生态系统的变化，特别是那些气温上升幅度最大的地区。在有些地区，这些变化是微不足道的，也许只有仔细的观测员才会注意到植被的轻微变化。而在其他情况下，气候的微小变化引发了一系列更大的影响，从而导致了巨大的变化。

2. The biggest climate-caused ecosystem shifts today are happening at the world's most northern latitudes, where the temperature over the last century has been rising about two times faster than the global average. In the northernmost state of the United States, Alaska, for example, warming has paved the way for a spike in the numbers of spruce bark beetles. Bark beetles have been a pest to Alaskan white spruce trees for thousands of years, but their numbers were held in check by the cold climate, which forced the insects to hide in the bark of individual trees for most of the year. As the length of the warm season increased over the 1980s and 1990s, however, bark beetles had more time to fly from one tree to the next, burrow, and lay their eggs between the bark and the wood. The beetles had another thing going for them, too: a multi-year drought had weakened many of the spruce trees, leaving them vulnerable to attack. In the mid-1990s, the bark beetle population exploded, and over the next few years the pests wiped out white spruce forests over an area the size of the U.S. state of Connecticut. In the years since, the combined forces of a longer insect-breeding season and forest management practices that left forests overcrowded gave way to similar epidemics farther south. Large swaths of pine and spruce have been destroyed by insects in several other parts of the United States.

在全世界北纬最高的地区，正发生着气候因素引起的最大的生态系统变化。在该地区，上世纪以来的气温上升幅度较全球平均水平快了约两倍。例如，在美国最北端的阿拉斯加州，气候变暖为云杉八齿小蠹虫数量的激增铺平了道路。数千年以来，对于生长于阿拉斯加州的白云杉来说，小蠹虫一直是一种害虫。但是由于寒冷的气候，它们的数量得到了有效的控制，寒冷的气候使得这种昆虫在一年中的大部分时间里都只能躲在担木的树皮内。然而，20世纪80年代至20世纪90年代以来，随着暖季时长的增长，小蠹虫有更多的时间从一棵树飞到下一个树，钻洞并将虫卵产在树皮和树木之间。另一件事情也助长了小蠹虫数量的增长：多年的干旱削弱了许多云杉树，使他们容易受到侵害。20世纪90年代中期，小蠹虫的数量呈现出爆炸式增长。在接下来的几年里，这种害虫彻底摧毁了大片的白云杉森林，面积大小相当于美国的康涅狄格州。在之后的几年中，更长的害虫繁殖季节，加上森林经营措施致使森林过于拥挤，使类似的疫情向更南的地区蔓延。在美国其他几个地区，大片大片的松树和云杉也被害虫破坏了。

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托福阅读真题题目：

1..The word subtle in the passage is closest in meaning to

A. limited

B. unimportant

C. not obvious

D. gradual

2..The phrase paved the way for in the passage is closest in meaning to

A. come together with

B. made possible

C. increased the intensity of

D. made absolutely certain

3..The phrase wiped out in the passage is closest in meaning to

A. damaged

B. threatened

C. spread through

D. killed off

4..Paragraph 2 suggests that the warming of the Alaskan climate affected bark beetles in which of the following ways

A. By making it possible for a beetle to deposit its eggs in a greater number of trees

B. By making it possible for beetles to survive in the bark of trees for longer lengths of time

C. By making it unnecessary for a beetle to protect its eggs by laying them between the bark and the wood

D. By increasing the number of spruce trees, thereby providing the beetles with far more places to live

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2015年7月11日托福阅读真题+题目+答案：Alaska and Bark Beetles，完整版下载，10元有偿！