托福真题阅读alaska and bark beetles答案及解析

托福真题阅读alaska and bark beetles答案及解析

1.答题解析：答案:C；Subtle：微妙的。所以选C。

2.答题解析：答案:A；

此段讲气候的影响讲了两点：（1）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.有更长的时间在树木之间来回穿梭并产卵。（2）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.使更多的数容易被攻击和理由，综合两点来看，deposit its eggs in a greater number of trees是可能实现的，A对。BCD均无支持。

3.答题解析：答案:A；第二段讲了spruce bark beetle epidemic in Alaska发生的过程，第三段讲了是the effects of the bark beetle epidemic，有好有坏，BUT之前讲的好的，BUT之后讲的坏的，D肯定不对，因为BUT之后为意思中心讲的是坏处。A讲后续events，即为the effects of the bark beetle epidemic意思

4.答题解析：答案:B；The grasses,in turn,changed the soil temperature,making the environment more friendly for some other types of vegetation.Animals that feed on grasses,including moose,elk,and some birds,also benefited.显然是B。

5.答题解析：答案是A和C；解析：Voles a type of small,mouselike rodent are an especially vital part of the ecosystem because they help spread mycorrhizal fungi,which attach to the roots of plants and help them take in water and nutrients.而现在Voles数量减少了，故C对D错。Voles are also an important food for a number of predators.，现在Voles数量减少了，A对，B无体现。

6.答题解析：答案:B。转折句，虽然ecosystem有恢复力，但是如果ALSKAN的生态系统被disturb太多，就可能恢复不了，而是变成另外一种生态系统。A只有“虽然”后的意思，没有“但是”后所强调的重要信息，C的Alaska might again become covered with woodlands or grasslands与原文“但是”后的信息相反，D的信息有错，原文说的是Alaskan spruce ecosystem是否能恢复，并非讨论一般的ecosystems。B的话是对原句的转述。

7.答题解析：答案:A；讲One such example is the coral reef die-off that happened in the Indian Ocean in the late 1990s.【其中一个例子就是上世纪90年代末发生在印度洋的珊瑚礁灭绝。】是为了印证前面的In extreme cases,major assaults on ecosystems can lead to a total collapse in which the ecosystem doesn’t bounce back to the way it was or transition to a new,healthy state.The result is an area with very little life;in the oceans,biologists refer to these areas as dead zones.，【在极端情况下，对生态系统的重大攻击可能导致生态系统的全面崩溃，无法恢复到原来的状态或过渡到一个新的、健康的状态。结果是一个几乎没有生命的区域;在海洋中，生物学家称这些区域为死亡区。】显然为A。D错在affected by a nearby dead zone

8.答题解析：答案:D；

ABC均无法回答，而第四段的In the short term,the Alaskan spruce beetle epidemic supplied a lot of people with firewood,but only by destroying tons of otherwise valuable timber and threatening the livelihoods of loggers.And no one knows for sure what the long-term impacts on the forest will be.【在短期内，阿拉斯加云杉甲虫的流行为人们提供了大量的柴火，但它摧毁了数吨原本很有价值的木材，并威胁到伐木工的生计。没有人确切知道对森林的长期影响会是什么。】长期effects不知，但一些短期effects，如有更多的木柴，所以D对，这里说的是some of the effects，不一定要知道total effects.

9.答题解析：答案:C；

前文应该提到this limited perspective，根据语境知指对人类的effects，即只看对人类的影响不看对整个生态的影响。后面要具体阐述为什么not completely straightforward。对应C，C前面说focus on the impacts on a single species:for instance,us.，C之后说短期可能有益，长期对人类影响未知，有坏有好，长短期effects不一样，故显得not completely straightforward.

10.答题解析：答案:A B C；

D错在epidemic in mycorrhizal fungi，原文讲的是Voles数量变少，影响到mycorrhizal fungi的扩散，并非造成了mycorrhizal fungi因传染病而亡。E的话，第四段说Ecosystem changes always hurt some living creatures and help others.It’s hard to say,therefore,whether a change is good or bad overall.。F的but after a transition period as a dead zone,they are able to return to their original state.没有体现。A注意到第二段论点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.B为第二段和第三段的概括，C为第四段和第五段的概括。