2022-06-28 16:49:34 来源：中国教育在线
一、The effects of environmental change on birds听力原文：
OK,so we've been looking at how man-made changes in our environment can affect wildlife.
Now I'll discuss a particular example.
Let's take a look at mercury.
Mercury's one of the 120 or so elements that make up all matter,and it has the symbol Hg.
It's a shiny,silvery substance.
You may have seen it in old-fashioned thermometers,but it's not used much for domestic purposes now because it's highly toxic.
But the problem is that the amount of mercury in the environment's increasing.
The main reason for this is the power plants used to produce electricity.
The main source of energy that most of them use is still coal,and when it's burned it releases mercury into the atmosphere.
Some of this gets deposited into lakes and rivers,and if it's ingested by a fish it's not excreted,it stays in the fish's body and it enters the food chain.
So it's been known for some time that birds which eat fish may be affected,but what wasn't known until quite recently is that those that eat insects can also be affected.
So a woman called Claire Varian-Ramos is doing some research on how this is affecting birds.
And rather than looking at how many birds are actually killed by mercury poisoning,she's looking for more subtle sub-effects.
And these may be to do with the behavior of the birds，or with the effect of mercury on the way their brain works,so whether it leads to problem with memory for example.
And she's particularly focusing on the effects of mercury on bird song.
Now，the process of song learning happens at a particular stage in the birds'development,and what you may not know is that a young bird seems to acquire this skill by listening to the songs produced by its father,rather than by any other bird.
And Varian-Ramos has already found in her research that if young male birds are exposed to mercury,if they eat food contaminated with mercury,then the songs they produce aren't as complex as those produced by other birds.
So quite low-level exposure to mercury is likely to have an impact on male birds in a natural situation,because it can mean that they're less attractive to female birds,and so it can affect their changes of reproduction.
Now the way she's carrying out this research is worth thinking about.
She's using a mixture of studies using birds kept in laboratories,and studies carried out outdoors in the wild.
The lab-based studies have the advantage that you don't get all the variables you would in a natural setting.
so the experimenter has a much higher level of control,and that means they can be more confident about their results in some ways.
And of course they don't have to worry about going out and finding the birds in order to observe them.
So what are the implications here for humans?
Well,because many birds are migratory they may be transporting mercury far from contaminated sites.
For example,it's been found that ducks who'd been feeding at a contaminated site were later shot by hunters over a thousand kilometres away and presumably eaten.
But these birds likely had mercury levels high enough to warrant concern for human consumption.
In addition,going back to song learning by birds,we saw that this may be affected by mercury contamination.
Well,we also know that in humans,mercury causes developmental delays in the acquisition of language,and in fact this process is very similar in the brain regions it involves and even the genes that are involved.
But mercury contamination has other important implications for humans as well.
It's now known that an unborn child can be affected if the food eaten by its mother contains high level of mercury,and these effects can be quite substantial.
In the end,it comes down to whether more value is placed on human economic wellbeing or environmental wellbeing.
It's true there are new regulations for mercury emissions from power plants,but these will need billions of dollars to implement,and increase costs for everyone.
Some argue that's too much to pay to protect wildlife.
But as we've seen,the issues go beyond that,and I think it's an issue we need to consider very carefully.
二、The effects of environmental change on birds听力中文翻译：
好的，我们一直在研究我们环境中的人为变化如何影响野生动物。
现在，我将讨论一个特定的示例。
让我们看看水星。
水星是构成所有物质的120种左右的元素之一，它的符号是Hg。
这是一种闪亮的银色物质。
你可能已经在老式的温度计上看到了它，但由于它的剧毒性，现在它在家用上没有太多用途。
但问题是环境中的汞含量正在增加。
主要原因是发电厂用来发电。
他们中的大多数人使用的主要能源仍然是煤炭，当煤炭燃烧时，会向大气中释放汞。
其中一些会沉积在湖泊和河流中，如果被鱼摄入，则不会排泄，而是留在鱼体内，进入食物链。
因此，一段时间以来，人们都知道吃鱼的鸟类可能会受到影响，但直到最近才知道吃昆虫的鸟类也会受到影响。
因此，一位名叫克莱尔·瓦里安·拉莫斯的女士正在研究这对鸟类的影响。
她并没有研究汞中毒究竟导致多少鸟类死亡，而是在寻找更微妙的副作用。
这些可能与鸟类的行为有关，也可能与汞对其大脑工作方式的影响有关，例如，汞是否会导致记忆问题。
她特别关注水星对鸟类鸣叫的影响。
现在，学习歌曲的过程发生在鸟类发展的特定阶段，你可能不知道的是，一只幼鸟似乎是通过听其父亲而不是任何其他鸟类发出的歌曲来获得这种技能的。
瓦里安·拉莫斯（VarianRamos）在她的研究中已经发现，如果年轻的雄性鸟类接触到汞，如果它们吃了受汞污染的食物，那么它们发出的歌曲就没有其他鸟类发出的歌曲那么复杂。
因此，在自然环境中，极低水平的汞暴露可能会对雄性鸟类产生影响，因为这可能意味着它们对雌性鸟类的吸引力较低，因此可能会影响它们的繁殖变化。
现在，她进行这项研究的方式值得思考。
她将实验室饲养的鸟类与野外进行的研究结合起来进行。
以实验室为基础的研究有一个优势，那就是你无法获得在自然环境中可能得到的所有变量。
因此，实验者的控制水平要高得多，这意味着他们可以在某些方面对自己的结果更有信心。
当然，他们也不必担心为了观察它们而去寻找鸟类。
那么，这对人类意味着什么呢？
嗯，因为许多鸟类都是候鸟，所以它们可能将汞运输到远离污染场所的地方。
例如，有人发现，在受污染的地方喂食的鸭子后来被1000公里外的猎人射杀，可能被吃掉了。
但这些鸟类的汞含量可能足够高，足以引起人们的关注。
此外，回到鸟类的歌唱学习，我们发现这可能受到汞污染的影响。
嗯，我们也知道，在人类身上，汞会导致语言习得的发育迟缓，事实上，这一过程在它所涉及的大脑区域甚至所涉及的基因中都非常相似。
但汞污染对人类也有其他重要影响。
现在已经知道，如果母亲吃的食物中含有高水平的汞，未出生的孩子可能会受到影响，而这些影响可能相当严重。
归根结底，这取决于人们是更重视人类的经济福祉还是环境福祉。
的确，对于发电厂的汞排放有新的规定，但这些规定需要数十亿美元才能实施，并增加每个人的成本。
一些人认为，保护野生动物的费用太高了。
但正如我们所看到的，问题远远不止于此，我认为这是一个我们需要仔细考虑的问题。
三、The effects of environmental change on birds听力问题：
Question 31-40
Complete the notes below.Write ONE WORD ONLY for each answer.The effects of environmental change on birds Mercury(Hg)•Highly toxic•Released into the atmosphere from coal•In water it may be consumed by fish•It has also recently been found to affect birds which feed on
Research on effects of mercury on birds•Claire Varian-Ramos is investigating:-the effects on birds'or mental processes,e.g.memory-the effects on bird song(usually learned from a bird’s)•Findings:-songs learned by birds exposed to mercury are less-this may have a negative effect on birds’•Lab-based studies:-allow more for the experimenter
Implications for humans•Migrating birds such as containing mercury may be eaten by humans•Mercury also causes problems in learning•Mercury in a mother’s body from may affect the unborn child•New regulations for mercury emissions will affect everyone’s energy
四、The effects of environmental change on birds听力答案：
31.insects
32.behavior/behaviour
33.father
34.complex
35.reproduction
36.control
37.ducks
38.language
39.food
40.cost/price/bill/costs/prices/bills
五、The effects of environmental change on birds听力答案解析
31.听前预测：定位词为feed on，此处应填名词。题目解析：原文为“what wasn't known until quite recently is that those that eat insects can also be affected."，故填insects。
32.听前预测：定位词为birds’，此处应填名词。题目解析：本题较容易，原文跟题目表达基本一致，定位至"And these may be to do with the behavior of the birds”，故填behavior。
33.听前预测：定位词为learned from，此处应填名词。题目解析：定位至"Listening to the songs produced by its father”。故本题填father。
34.听前预测：定位词为less，此处应填形容词。题目解析：本题出题句为“aren’t as complex as those produced by other birds.”，本题所需的词为complex。
35.听前预测：定位词为negative effect，此处应填名词。题目解析：根据“it can affect their changes of reproduction"可知要填reproduction。
36.听前预测：定位词为more，此处应填名词。题目解析：考点句为“so the experimenter has a much higher level of control”，此处填名词control。
37.听前预测：定位词为migrating birds，此处应填名词。题目解析：定位至“Well,because many birds are migratory they may be transporting mercury far from contaminated sites.For example，it's been found that ducks who'd been feeding at a contaminated site were later shot by hunters over a thousand kilometres away and presumably eaten.”，故本题空处需填ducks。
38.听前预测：定位词为problem,learning，此处应填名词。题目解析：出题句为“we also know that in humans.Mercury causes developmental delays in the acquisition of language”，本题答案为language。
39.听前预测：定位词为from,此处填名词。题目解析：定位至“It's now known that an unborn child can be affected if the food eaten by its mother contains high level of mercury”，故此填food。
40.听前预测：定位词为energy,此处填名词。题目解析：定位至“It's true there are new regulations for mercury emissions from power plants,but these will need billions of dollars to implement,and increase costs for...”，故此填cost。
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