阅读jj passage213讨论～～求大神解答啊

啊GRE好难UID: 4043665

这篇文章的选项真的看得我头疼orz。。。还有就是答案分歧好严重，两个题我都做错了～求大神答疑qwq

passage 213
There have been numerous well-documented extinctions of indigenous species caused by the introduction of nonindigenous predators and pathogens. However, surprisingly few extinctions of indigenous species can be attributed to competition from introduced species. For example, during the past 400 years, 4,000 plant species have been introduced into North America, and these nonindigenous plants currently account for nearly 20 percent of North America’s plant species. Yet no evidence exists that any indigenous North American plant species became extinct as a result of competition from introduced plant species. The scarcity of documented extinctions caused by competition from new species could mean that such extinctions take longer to occur than scientists initially believed or, alternatively, that extinctions are rarely caused by competition from nonindigenous species.

1.The passage is concerned primarily with：
【我选的是B，维夕答案是A，微臣答案是B。但是仔细细考完我觉得是我错了！我又觉得应该选A了惹。问：你pick什么？】
A. Pointing out that a particular type of species extinction is rarely known to occur （正确。注意：a particular type of species extinction 指的是extinctions due to introduced species）
B. Proposing a possible explanation for conflicting data about a particular type of species extinction  
（B错在这个对于conflicting data的理解，虽然第一句提到了”well-documented extinctions caused by the introduction of nonindigenous…” ，但是这与第二句话并不contradict，需要区分nonindigenous predators捕食者 and pathogens病原体 和nonindigenous species物种不代表同一个东西，后者的范围更大 ；我们可以说“外来物种导致的物种灭绝”被很少记录，也同时说“外来食肉动物和病原体导致的物种灭绝”被记录得很多，所以“However..,”这一句话并没有办法在逻辑上反驳第一句话。）
C. Resolving a debate about the frequency of a particular type of species extinction (debate is not mentioned as it requires two opposing viewpoints. There is only one viewpoint throughout the whole passage. Note: the first sentence is NOT a viewpoint but a background information regarding the current documentation of the cause indigenous species extinctions)
D. Comparing two theories regarding possible causes of a particular type of species extinction （theories not mentioned in the passage)
E. Refuting a proposed explanation for the increasingly rare occurrence of a particular type of species extinction (Passage did not refute any explanations, 反倒是在最后一句话解释了scarcity of the documented extinctions caused by introduced species 的原因，其次没有提到increasingly rare，只提到了scarcity)



2. The author introduces statistics about North America’s nonindigenous plant species primarily in order to 【我选的C，微臣和维夕答案都是E，但晚上答案有分歧，问E为什么对？？还有A应该怎么理解】
A. undermine a proposed explanation for the absence of any evidence for the occurrence of a particular phenomenon.（？？ ）
B. contrast the effect of introduced plant species in North America with the effect that introduced animal species have had. (animal species没有提到，简单排除)
C. suggest that North America’s indigenous plants are a domain（领域） in which there has been ample scope（足够的范围） for a particular effect to have occurred.
D. emphasize how much the ecology of North America has been affected over the past 400 years by the introduction of nonindigenous species (not the main objective of this sentence 太肤浅了)
E. substantiate a claim about the overall effect that the introduction of nonindigenous species tends to have on indigenous populations.  （we cannot generalize this to the “overall effect” since the bolded sentence only mentioned North American species, 另外通过这些数字我们好像不能直接判断introduction of nonindigenous species的影响程度，20%是多还是少？只能证明有影响 ）

williennelsonUID: 3748652

1. 答案B
A. 作者不只是指出某一类灭绝少见,而是为了指出造成这个现象少见的原因。错
B. 作者对一个看似矛盾的现象提出了解释
2.答案C
A. undermine,错误,这句话是作为例子支持前面的内容,并没有undermine
C. 为了体现北美的本地物种有足够的机会(有很多入侵物种) 让某一种影响(入侵物种的竞争导致本地物种灭绝)发生,正确,突出了后面“实际并没有发生”的surprising。
E. 错误。这句话的确是作为例子中的一个部分,支持了前面说的“奇怪的是很少有证据证明外来物种的竞争导致了本地物种的灭绝”,但是这只是关于外来物种竞争对于本地物种的影响,而不是外来物种整体(overall)对于本地物种的影响。
---来自万炜