Today I'm going to talk about invasive species. Let me start by saying what an invasive species is and what it's not. Invasive species are any animal or plant that is introduced into an environment by humans, and which is then harmful to that environment. It's important to be clear that not all introduced species are invasive. Many introduced – or non-native – species thrive in new areas without posing any threat.

In some cases, invasive species have changed the natural world beyond recognition, so let's look at the different ways they can be problematic. First of all, invasive species may eat native species, or sometimes they may bring a disease【Q31】 with them, which native species have never faced before and therefore have no defences against. Often the invasive species breed very quickly – which further adds to the problem of native species losing their sources of food. Species invasions are one of the biggest causes of damage in an ecosystem【Q32】, actually putting its survival at risk.

So, how do invasive species spread? Without a doubt, the biggest cause is human activity. This could be intentional, or it could be accidental, such as when people who've been on holiday【Q33】 in another country come back with, say, the seeds of plants on their clothes or shoes. Plants and animals, especially insects, arrive in or on the cargo of ships, and then escape into their new 'home'. But sometimes humans deliberately move animals and plants around the world, for example to use them to control pests on farms, or to be pets【Q34】. This can go very wrong if those animals and plants move into wild settings and start breeding or begin growing in ways that weren't predicted.

Let's now look at an example of an invasive species here in Australia: Rhinella marina is a species of toad that was deliberately introduced from Hawaii in 1935 as a form of biological control. It was hoped that the toads would eat the grey-backed beetles responsible for destroying crops of sugar【Q35】on many of the plantations. At first, just a handful of toads were released by scientists into Queensland, but this number soon grew as other states followed suit. Within two years, 62,000 young toads had been released into the wild. The toads did nothing to protect the plantations, but they did reproduce rapidly and could soon be found all over the northern half of the country. The toads are poisonous at every stage of their life cycle, and anything that eats them will die.

My second example regarding invasive species is the United Kingdom. Actually, there are more than three-thousand invasive species there, including some that are extremely common. Some invasive plants, such as Japanese knotweed, have had a devastating impact on parts of the UK. Gardeners in the nineteenth century considered it a beautiful ornamental plant – which it is, when it's kept under control – but it soon spread into the countryside and remains a problem even to this day as it's so hard to eradicate. Another invasive plant is rhododendrons, which can be found in UK parks and woodlands. Their introduction dates back to 1763, but they're now seen as harmful because they block out so much light【Q36】 that native wild flowers can't grow beneath them.

And then there are grey squirrels, which are one invasive species almost everyone in the UK will have come across. They were brought to the UK from North America and introduced to private estates around the 1870s but are now found everywhere, from forests to city squares. Grey squirrels have outcompeted the smaller, native red squirrels. They both eat the same food, and the grey squirrels carry a type of virus【Q37】 that is deadly to the red squirrels. Red squirrel populations have collapsed, and there are only a handful of sites left in the UK where they're found.

An important question for ecologists worldwide is, what can we do to tackle the problem of invasive species? The first step in controlling invasive species is learning about the behaviour【Q38】 of new species coming into the country. Monitoring is an important part of this, so that we can know if the new species begins to have a negative impact in its new environment. One effective way to keep track of invasive species is to create a database【Q39】 for the whole country. That way, all relevant authorities and agencies can share important information and take whatever action's needed. But the public also have a vital role to play in this process. They should be encouraged to photograph【Q40】 harmful species – because this helps with identification – and then to report when and where these were observed. But it's important to tell people not to destroy or even touch what they've found.

Now, I'm going to move on to ...

Questions 31-40

Complete the notes below.

Write ONE WORD ONLY for each answer.

答案与解析
练习推荐
我的答案
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正确答案
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disease
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ecosystem
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holiday或holidays
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pets
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sugar
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light
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virus
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behaviour或behavior
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database
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photograph
题目解析

听前预测:定位词 native species,提示词为 problem、introduces a new。此处填单数可数名词,内容为入侵物种带来的某项问题。

题目解析:在本题定位信息 native species 附近先听到 First of all, invasive species may eat native species, 意为“首先,入侵物种可能会捕食本地物种”,对应本题上一行的定位信息,也是入侵物种带来的第一个问题,注意开始带着预判目标听。听到 or sometimes they may bring a disease with them, which native species have never faced before and therefore have no defences against,意为“或者有时它们会携带某种疾病,而本地物种从未遇到过这种疾病,因此对其没有任何防御能力”。其中 or 代表逻辑关系,衔接下一项入侵物种带来的危害,disease 符合目标导向,原文中的 bring 对应题干中的 introduces,后续 which 引导的从句是对题干的 new 的具体描述,进一步确认 disease 为正确答案。

听前预测:定位词为 food,提示词为 threatens an entire。此处应填单数名词,内容为被入侵物种威胁的对象。

题目解析:本题先听到“Often the invasive species breed very quickly—which further adds to the problem of native species losing their sources of food.”,意为“入侵物种通常繁 殖得非常快——这进一步加剧了本地物种失去食物来源的问题。”其中 food 为 本题的前置定位词,准备开始带着预判目标听。听到“Species invasions are one of the biggest causes of damage in an ecosystem, actually putting its survival at risk.”,意为“物种入侵实际上是生态系统受损的最大原因之一,甚至会危及生态系统本身的存续。”其中 ecosystem 符合预判的内容方向,为正确答案。原文中的 one of the biggest causes of damage 对应题干 threatens,而题干中的 entire 则隐含在全句内容中,(整个)生态系统都会受到威胁。注意听时不要盯着挖空位置附近题干的单词去找,而是带着目标听信息,直接识别答案即可。

听前预测:定位词为 people、cargo ships,提示词为 accidentally、returning from their。此处应填名词,内容为入侵物种意外扩散的相关信息,具体来自人类,而这些人应从特定某处或某种特定情况、条件下回来。

题目解析:本题先通过设问句开始,“So, how do invasive species spread?”意为“那么,入侵物种是如何传播的呢?”提示小标题信息 how invasive species spread。随后,先听到总括介绍“Without a doubt, the biggest cause is human activity.”,意为“毫无疑问,最大的原因就是人类活动。”继续听到 This could be intentional, or it could be accidental,意为“这可能是故意的,也可能是偶然的”,其中 accidental 符合本题相关信息的提示,注意带着目标识别。听到开始举例,such as when people who've been on holiday in another country come back with, say, the seeds of plants on their clothes or shoes. Plants and animals, especially insects, arrive in or on the cargo of ships, and then escape into their new ‘home’ 意为“例如去国外度假的人回国时,衣服或鞋子上可能带回植物的种子。动植物,尤其是昆虫,会附着在船舶货物的内部或表面到达,然后逃逸到它们新的‘家园’中”。其中 holiday 符合目标预判方向,代入命题意为入侵物种通过人们度假被意外带回,原文中的 come back 对应题干中的 returning,而下一句的 cargo of ships 对应题干中的定位信息 cargo ships,进一步确认 holiday 为答案。注意原文中的 country 不符合 their 的用词搭配,如果填写上去表达的信息是从他们的国家回来,不符合原文语义以及实际常识,不能填写。本题命题的一句话,在原文被扩展为两个长句,注意不要按照讲话的内容多少判断答案是否错过,题干和文本是浓缩的关系。

听前预测:定位词为 pest control,提示词为 or as。此处应填名词,内容为入侵物种有意传播的目的。

题目解析:转折词 but 提示逻辑的转换,对应本个小标题下第二个点。带着目标识别信息,先听到 But sometimes humans deliberately move animals and plants around the world, for example to use them to control pests on farms,意为“但有时人类会故意将动植物运往世界各地,例如将它们用于农场害虫防治”,原文 control pests 对 应题干的定位信息 pest control,继续听。注意代表选择关系的并列连词 or 后出 现的信息 or to be pets,意为“或作为宠物饲养”,其中 pets 符合预判方向,为正确答案。后续信息扩展描述这些人为引入的入侵物种的影响“This can go very wrong if those animals and plants move into wild settings and start breeding or begin growing in ways that weren't predicted.”,意为“如果这些动植物进入野外环境并开始以出乎预料的方式繁殖或生长,就可能会引发严重问题。”这一内容为本小标题下的衔接信息,属于与做题无关的冗余内容,但是对于理解入侵物种的影响有所帮助。

听前预测:定位词为 Australia、Hawaii、1935、insect、plantations,提示词为 damaging、plantations。此处填名词或形容词,用于描述受损种植园的特点或类型。

题目解析:先听到 Let's now look at an example of an invasive species here in Australia,意为“现在让我们来看一个澳大利亚入侵物种的例子”,提示本题小标题相关信息 examples of invasive species,以及题干定位信息 Australia 的出现。注意带着目标识别答案,Rhinella marina is a species of toad that was deliberately introduced from Hawaii in 1935 as a form of biological control,意为“海蟾蜍(Rhinella marina)是一种蟾蜍,于 1935 年作为生物防治手段从夏威夷被有意引入”,对应了题干定位信息 Hawaii 及 1935,但是还未出现种植园的相关信息,继续耐心听。听到“It was hoped that the toads would eat the grey-backed beetles responsible for destroying crops of sugar on many of the plantations.”,意为“人们原本希望这些蟾蜍能吃掉那些对许多种植园糖料作物造成破坏的灰背甲虫。”其中 crops of sugar 符合预判的方向,且在定位信息 plantations 附近出现。但是由于答案只能填写一个词,要选择能够从语法、词汇上符合命题的表达。如果填写 crops,形成的表达为 crops plantations,从语法语义上来说都不合理。从语法上来说,一般都是单数名词修饰另一个名词;从内容上来说,作物和种植园是包含关系, 无法形成修饰关系。而 sugar plantations 意为“甘蔗种植园”,通顺合理,故为正确答案。

听前预测:定位词为 rhododendron plants,提示词为 prevent…from,此处应填名词,内容为该植物阻止的对象。

题目解析:经过漫长的等待,先听到本题相关的定位信息“Another invasive plant is rhododendrons, which can be found in UK parks and woodlands.”,意为“另一种入侵植物是杜鹃花,在英国公园和林地中常见。”注意准备好带着预判目标识别答案信息。听到“Their introduction dates back to 1763, but they're now seen as harmful because they block out so much light that native wild flowers can't grow beneath them.”,意为“它们引入英国的历史可追溯至 1763 年,但现在被视为有害植物,因为它们遮挡了大量阳光,导致本土野花无法在其下方生长。”其中 light 是该种入侵物种核心危害本土植物的因素,符合预判方向。原文中的 block out 对应题干信息 prevent…from,而题干中的 native plants,在原文中具体对应 为 native wild flowers,进一步确认 light 为正确答案。

听前预测:定位词为 grey squirrels、N. America、red squirrels,提示词为 spread a、that kills red squirrels。此处应填单数可数且以辅音开头的名词,内容为杀死红松鼠的对象。

题目解析:先听到逻辑信号词 then,随后衔接题干定位词 grey squirrels,确认本题正式开始。“And then there are grey squirrels, which are one invasive species almost everyone in the UK will have come across.”意为“还有一种入侵物种是灰松鼠,这几乎是每个英国人都曾遇见过的入侵物种。”继续听。带着预判目标判断识别信息,“They were brought to the UK from North America and introduced to private estates around the 1870s but are now found everywhere, from forests to city squares.”意为“它们于 19 世纪 70 年代左右从北美被带到英国,并被引入私人庄园,但如今从森林到城市广场,到处都能见到它们的身影。”虽然听到很多信息,其他题干定位信号也进一步出现,但是没有识别到能够杀死红松鼠的信息,故而继续耐心地听。听到“Grey squirrels have outcompeted the smaller, native red squirrels. They both eat the same food, and the grey squirrels carry a type of virus that is deadly to the red squirrels.”,意为“灰松鼠已经竞争过了体型较小的本地红松鼠。两者以同样的食物为食,但灰松鼠携带一种对红松鼠致命的病毒。”其 中 virus 符合预判方向,且原文的 deadly to the red squirrels 对应题干 kills red squirrels,进一步确认 virus 为答案。继续听到“Red squirrel populations have collapsed, and there are only a handful of sites left in the UK where they're found.”,意为“红松鼠的数量已经崩溃,如今英国只剩下少数几个地方还能见到它们。” 该内容为英国本土红松鼠受到外来物种影响的进一步描述,补充题干 kills red squirrels 这一信息。注意本题题干的一句话,被扩展为整整一段话,做题一定要耐心,且目标明确。

听前预测:定位词为 monitoring,提示词为 understand the、of invasive species。此处应填名词,内容为借助监测行为帮助人们了解入侵物种的相关信息。

题目解析:听到设问信息,对应本题的小标题信息“An important question for ecologistsworldwide is, what can we do to tackle the problem of invasive species?”,意为“全球生态学家面临的一个重要问题是:我们能做些什么来应对入侵物种的问题?”准备开始带着目标识别答案。先听到“The first step in controlling invasive species is learning about the behaviour of new species coming into the country.”,意为“控制入侵物种的第一步是了解进入本国的新物种的行为。”虽然还没有听到定位信息 monitoring,但是 behaviour 一词符合预判方向,先试填写。继续听到“Monitoring is an important part of this, so that we can know if the new species begins to have a negative impact in its new environment.”,意为“监测是其中重要的一环,这样我们才能知道新物种是否开始对新环境产生负面影响。”终于等到 定位信息原词出现,且后续文本中 negative impact in its new environment 对应题干后半句 the impact they have,故而进一步确认 behaviour 为合理的答案信息。

听前预测:定位词为 national,提示词为 setting up、easier to track them。此处应填单数名词,内容为便于追踪入侵物种的对象,且是全国范围内的。

题目解析:本题先听到 track,对应题干信息,注意带着目标识别。“One effective way to keep track of invasive species is to create a database for the whole country.”意为“追踪入侵物种的一个有效方法是为全国建立一个数据库。”其中 database 符合预判方向,而题干定位信息 national 在原文被替换为 for the whole country,进一步确认其为答案。

听前预测:定位词为 the public,提示词为 to、helps with monitoring。此处应填动词原形,内容为公众做的动作,有助于监控入侵物种。

题目解析:先注意到转折信号词 but,配合题干定位信息 the public,确认本题正式开始。“But the public also have a vital role to play in this process.”意为“但公众在这一过程中也扮演着至关重要的角色。”注意识别大众的行为,“They should be encouraged to photograph harmful species—because this helps with identification— and then to report when and where these were observed.”意为“应该鼓励他们对有害物种进行拍照——因为这有助于识别——然后报告观察到的地点和时间。” 其中 photograph 为动词词性,原文对拍照的作用进一步阐释,随后听到题干另 一并列动作 report,进一步确认拍照为答案。后续信息“But it's important to tell people not to destroy or even touch what they've found.”,意为“但重要的是,要告诉人们不要破坏甚至触碰他们所发现的东西。”虽然 destroy 和 touch 出现在转折词 but 之后,但是这两个词都是劝阻公众做的、被否定的动作,故为干扰信息。不要迷信 but,其后不是 100% 出答案,只是概率问题。

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