想要在托福阅读考试中获得高分，平时就要多阅读一些英语类的文章，不断提高理解能力，增加背景知识。今天小编为大家带来的是一篇关于“外来物种”的托福阅读文章，并对文章进行了详细的分析，大家一起来学习一下吧。
内容提要：
一、背景知识
二、文章讲解
三、重要词汇
四、题目分析
一、背景知识
1. 外来物种的定义：
出现在其自然分布范围和分布位置以外的一种物种;
必须是外来的、非本土的;
能在当地的自然或人工生态系统中定居、自行繁殖和扩散，最终明显影响当地生态环境、损害当地生物多样性。
2. 人类是如何引入外来物种的?
1)有意引种(Intentional introduction)
2)有意引种(Unintentional introduction)
二、文章讲解
Go forth and multiply
WHAT makes for a successful invasion? Often, the answer is to have better weapons than the enemy. And, as it is with people, so it is with plants—at least, that is the conclusion of a paper published in Biology Letters by Naomi Cappuccino, of Carleton University, and Arnason, of the University of Ottawa, both in Canada.
怎样才能成功入侵?答案常常是：拥有比敌人更好的武器。人是这样，植物也是如此——至少，《生物书简》上发表的一篇论文是这么认为的，作者是来自加拿大加里敦大学的纳奥米•卡普奇诺和渥太华大学的索尔•阿纳森。
The phenomenon of alien species popping up in unexpected parts of the world has grown over the past few decades as people and goods become more mobile and plant seeds and animal larvae have hitched along for the ride. Most such aliens blend into the ecosystem in which they arrive without too much fuss. (Indeed, many probably fail to establish themselves at all—but those failures, of course, are never noticed.) Occasionally, though, something goes bananas and starts trying to take the place over, and an invasive species is born. Dr Cappuccino and Dr Arnason asked themselves why.
过去的几十年，随着人和货物的流动日益频繁，植物种子和动物幼体也乘机“搭便车”四处播散，世界各地无意间出现了越来越多的外来物种。这些外来物种大多数都轻而易举地融入了所到之处的生态系统。(事实上，许多物种可能还没有站稳脚跟——当然，人们从未注意到这一点。)不过，偶尔也有某些物种疯狂繁殖，开始企图占领原有物种的生长空间，一种入侵物种就这样形成了。卡普奇诺和阿纳森对此感到百思不得其解。
One hypothesis is that aliens leave their predators behind. Since the predators in their new homelands are not adapted to exploit them, they are able to reproduce unchecked. That is a nice idea, but it does not explain why only certain aliens become invasive. Dr Cappuccino and Dr Arnason suspected this might be because native predators are sometimes “pre-adapted” to the aliens' defences, but in other cases they are not.
有人推想，外来物种摆脱了原先的掠食者，而在新的“家园”，现有的掠食者又没有发现它们也合口味，因此这些物种得以肆无忌惮地繁衍。这种观点好是好，不过没有解释为什么只有特定的外来物种才具有入侵性。卡普奇诺和阿纳森猜测，这可能是因为土生土长的掠食者对外来物种所具有的防御机制有时产生“预适应”，有时又不产生。
To test this, they had first to establish a reliable list of invaders. That is not as easy as it sounds. As they observe, “although there are many lists of invasive species published by governmental agencies, inclusion of a given species in the lists may not be entirely free of political motivation”. Instead, they polled established researchers in the field of alien species, asking each to list ten invasive species and, for comparison, ten aliens that just rubbed along quietly with their neighbours. The result was a list of 21 species widely agreed to be invasive and, for comparison, 18 non-invasive aliens.
为了证实这一猜测，他们必须首先列出一些已经确认的入侵物种。这可不是件轻松的事。正如他们所说，“虽然政府部门公布了许多入侵物种名单，但是把指定物种归入此名单也许多少有些出于政治上的考虑。” 为此，他们调查了外来物种领域一些有名望的研究人员，请每人举出10种入侵物种，以及10种与本地物种能和睦共生的外来物种用于对照。最后得到的名单中包括21种被广泛认可的入侵物种和18种用于对照的非入侵性外来物种。
三、重要词汇
1. make for 走向，促进
If the ship encountered strong wind, it should make for port.
What makes for a successful invasion?
2. pop up突然出现
Mushrooms tend to pop up overnight.
The phenomenon of alien species popping up in unexpected parts of the world has grown over the past few decades.
3. hitch免费搭车
We hitched a ride with a car from New York to Washington.
Plant seeds and animal larvae have hitched along for the ride.
延伸：hitch n.故障，障碍
Except for a few technical hitches, the show went very well.
The graduation party went off without a hitch.
4. blend into融入，与……融合
The sea and the sky seemed to blend into each another.
Most such aliens blend into the ecosystem in which they arrive without too much fuss.
引申：blend in+with与……协调
The old house blends in perfectly with the atmosphere of the countryside.
The curtains blend in perfectly with the furniture.
5. go bananas发疯
bananas adj.发疯的，愚蠢的
The drugs have made him go bananas.
Occasionally, though, something goes bananas and starts trying to take the place over.
延伸1：drive sb. bananas/nuts
He has driven his wife bananas ( nuts ).
延伸2：top banana喜剧的主角→老板或上司
He is the top banana in this corporation.
6. unchecked不受限制的
We cannot allow such behavior to continue unchecked.
Since the predators in their new homelands are not adapted to exploit them, they are able to reproduce unchecked.
7. rub along (with)(跟某人)关系维持得不错;相处得不错
My wife and I seem to rub along (together) all right.
To list ten aliens that just rubbed along quietly with their neighbors.
四、题目分析
One hypothesis is that aliens leave their predator's behind. Since the predators in their new homelands are not adapted to exploit them, they are able to reproduce unchecked. That is a nice idea, but it does not explain why only certain aliens become invasive.
What does “they" refer to?
A. The predators
B. New homelands
C. Aliens
D. Hypothesis
解析：这是一道指代题，解答指代题的原则是先往前看，后往后看。一般情况下，代词所指代的内容就是前面一句话的主语，当然也有例外的情况，这道题就属于例外的情况。那我们就先看一下后面的一句话：“That is a nice idea, but it does not explain why only certain aliens become invasive.”前面提到一个假说，最后一句之前的内容都是在解释这个假说，而最后一句话是对前面假说的一种评价，因此，最后一句话和前文是两种不同的关系，所以，代词“they”不可能指代后面的“nice idea”。那么我们就只能往前找了。前面讲的是，一种假说认为外来物种摆脱了掠夺者，由于掠夺者在新的家园里对这些外来物种还不太感兴趣，因此“它们”能够不受约束地疯狂繁殖。根据句意，代词they指代的应该是外来物种。因此，正确答案应该是C选项。
以上就是小编为大家带来的英语阅读文章分析，希望能给考生的学习带来帮助。最后，小编祝愿各位考生在托福考试中取得好成绩!
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