阅读求助2
There have been numerous well-documented extinctions of indigenous species caused by theintroduction of non-indigenous 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 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.
2. The author introduces statistics about North America’s non-indigenous plant species primarily in
order to
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
C. suggest that North America’s indigenous plants are a domain in which there has been ample
scope 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 non-indigenous species
E. substantiate a claim about the overall effect that the introduction of non-indigenous species
tends to have on indigenous populations
我觉得C更好, 答案E, 有谁能告诉我C错在哪? 题目问作者引用北美外来植物品种的数据主要是为了什么，因此我们要做的就是找到对应句子所在的那层逻辑关系.
我们来简要分析一下文章的行文结构：描述现象(大量有卷宗记录的物种灭绝是由于外来物种的引入)→However引出相反的现象(很少有物种灭绝是由于和外来物种的竞争)→一个eg.来说明这种exception(也就是题目中提到的statistics)→Yet是对eg.的进一步分析(eg.的这种pattern意味着要么1 ni.s. eliminate i.s.的这种extinctions比科学家所设想的时间要长；要么2 其实extinctions很少是由于这种pattern).
C错就错在它true but irrelevant，因为它回答的其实是这个eg.本身揭示了什么，而不是作者引用这个eg.是为了说明什么。 我也觉得C好。20% 接的是没有什么本地植物因此灭绝。这个没有本地植物因此灭绝才对应E，20%对应的是C。 题目问这个20%是什么用。楼上非要说题目问的是这个例子是什么用。这就是强词夺理啊。 我看出来问题了。 C里面这个domain标错了。这个ample scope是结合20%的外来物种才有的opportunity 去灭绝。C要对就把indigenous去掉。谈一个物体对另一个物体的影响，很难把其中一个物体单独标出来说怎么样怎么样，一定要提及另一个的。c就是domain的问题。 本帖最后由 我Me是个好人 于 2017-8-19 12:32 编辑
synz 发表于 2017-6-18 13:55 static/image/common/back.gif
我也觉得C好。20% 接的是没有什么本地植物因此灭绝。这个没有本地植物因此灭绝才对应E，20%对应的是C。 题目 ...
这个强词夺理...
题目问的就是The authorintroduces statistics about North America’s non-indigenous plant species是为了什么, 也就是问你作者的意思, 而不是这些数据本身的意思.
然后这些数据是在For example之后出现的, 所以作者援引它们一定是为了支持在它们之前出现的statement, 也就是few extinctions of indigenous species can be attributed to competition from introduced species.
E中的claim就是我上面提到的这个statement, 而claim后面的内容则只是将这个statement做了一个paraphrase: 很少有本地物种的灭绝可以被归咎于外来物种的引入, 也就是讨论"外来物种的引入对本地物种的数量的影响"的问题, 于是我们看到了关键词overall effect. 选E.
从20%中我们自然可以infer出indigenous plants are a domain没错, 甚至更进一步我们也可以infer出说there has been ample scope for a particular effect to have occurred, 这些都对, 但这些都只是我们能从这些数据本身出发infer出的东西, 而不是说作者原因这些数据是为了什么, 所以就和题目所问无关了. 要体现E的意思的话，光有外来物种的数据（4000,20%）显然远远不够，要和后面的“Yet no evidence exists that any..”结合起来才能说明。
作者引用这组数据显然是想说明当地植物种类数量足够多，如果某类灭绝能发生的话总能发生的。 C是在说数据eg本身的内容，题目问eg的作用！
没有转折取反 自然是支持前面的观点了~ 我服了，今年的教材答案是C 今年的教材是哪本啊？我把official guide 第三版都翻了一遍，也没找到这篇阅读啊。。 洛流沁 发表于 2019-9-20 14:59 static/image/common/back.gif
今年的教材是哪本啊？我把official guide 第三版都翻了一遍，也没找到这篇阅读啊。。
是阅读200篇 这道题答案有的给C有的给E 这道题如果有最好的答案那就是C
The author introduces statistics about North America’s non-indigenous plant species primarily in order to
这里重点是stats，原文的stats是
For example, during the past 400 years, 4,000 plant species have been introduced into North America, and these non-indigenous plants currently account for nearly 20 percent of North America’s plant species.
这仅仅是stats，没有给出implications。而问题刚好问的也是作者的目的，刚好下句话是转折：
Yet that no evidence exists that any indigenous North American plant species became extinct as a result of 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 non-indigenous species.
试问：
为什么要以北美为例子，或者说北美例子的数据有什么特点？
这里为什么要转折？
上述第一问的答案，是因为北美短时间内（400年在生物进化里算短了吧？不是生物专业的还请指正）引入了大量的外来生物(4,000 plant species have been introduced into North America)，并且这些外来生物还大量繁殖（nearly 20 percent of North America’s plant species），所以相对来说是，如果一开始的假设“extinctions of indigenous species can be attributed to competition from introduced species”成立的话，北美就会发生大量因竞争导致的灭绝，所以这个地方才是a domain in which there has been ample scope for a particular effect to have occurred
第二问的回答，为什么要转折？因为这样的灭绝没有发生
因此综上，这种灭绝要发生的话，北美早就大量发生了，因为北美是一个这种灭绝的良好的温床，但是事实上并没有发生（至少根据原文如此）
再看选项里的
suggest that North America’s indigenous plants are a domain in which there has been ample scope for a particular effect to have occurred
"for a particular effect to have occurred"
正是没有occur
再说E. substantiate a claim about the overall effect that the introduction of non-indigenous species
tends to have on indigenous populations
如果要倾向于E，那么躲不过的就是“overall”以及原文也提到了“numerous well-documented extinctions of indigenous species caused by the introduction of non-indigenous predators and pathogens”。
是否可以在选项已经明确说明是“overall effect”的情况下，且并没有限定为one particular type of extinction，依然认为这句话是符合作者意见的呢？
若是如此的话，那么本文应该讨论the introduction of non-indigenous species
tends to have on indigenous populations的 the overall effect，包括了第一句话里提及的effect
个人拙见还请指正
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