托福听力该怎样突破呢

Pigeons. Ever since humans established permanent agricultural settlements, we've lived side-by-side with the birds—or, as some people call them, rats with wings. They walk on our sidewalks, roost on our buildings, and eat our leftovers. But soon pigeons may help us identify risks to public health.

"What we're doing here in my lab is we're assessing how we can use something that's been considered a pest that people actively try to exterminate: the pigeon. How can we use it to better the environment for not only ourselves but for pigeons and for other wildlife?"

U.C. Davis neurobiologist Rebecca Calisi. She looked at lead levels in blood samples from more than 800 injured pigeons brought to a New York City wildlife rehabilitation center. And she compared those to lead levels in blood samples collected from children by the New York City Department of Health in routine screening efforts. The results were published in the journal Chemosphere.

"The neighborhoods where children have high rates of lead toxicity, that's where we saw pigeons with high blood lead levels...so this is a proof of concept kind of project."

Most pigeons will live out their lives within just two kilometers of the place they hatched, so the birds may be able to help researchers develop a detailed map of the risk of toxic lead exposure.

In people, especially kids, lead exposure can affect intelligence, brain development, social skills and memory. Having demonstrated that pigeons can pinpoint areas with high lead contamination, Calisi thinks that the birds can help researchers zero in on other potential environmental hazards as well.

"The thing is, we don't know what to test for right now. We know to test for lead, but what about certain pesticides? Or fire retardants are a big problem these days. We're not sure what the problems are. So instead of drawing a ton of blood from children and putting them through all these tests, why not use an animal that shares our environment, the pigeon, and test for a whole suite of different potential harmful pollutants?"

So rather than dismissing them as rats with wings, why not think of them as...lab rats with wings?

鸽子。自从人类建立永久性农业定居点以来，鸽子就一直与我们生活在一起，甚至有一些人称鸽子是有翅膀的老鼠。鸽子走在人行道上，栖息在建筑楼顶，吃我们的剩饭剩菜。但是不久以后鸽子可能会帮助我们确定公共卫生风险。

“我们正在实验室里评估如何使用被人们认为是害虫且一直想要消灭的动物：鸽子。我们怎么用鸽子更好地保护环境，不仅对我们人类有利，同时也对鸽子和其他野生动物有利?”

丽贝卡·卡利斯是加州大学戴维斯分校的神经生物学家。她对纽约市野生动物康复中心800多只受伤鸽子血液样本中的铅含量进行了研究。并将这些同从纽约市卫生局常规检查中收集来的儿童血液样本中的铅含量进行了比较。结果发表在《Chemosphere》杂志上。

“社区儿童高铅毒性的地方，也就是我们看到鸽子高血铅水平的地方……这是项目所证实的概念。”

大多数鸽子生活在距离它们的出生地只有2公里的地方，所以这种鸟类也许可以帮助研究人员绘制详细的铅毒风险地图。

对人们来说，尤其是对孩子来说，铅暴露会影响智力、大脑发育、社会技能和记忆力。卡利斯已经证明鸽子可以确定高铅污染的地区，她认为鸟类也可以帮助研究人员发现其他潜在的环境危害。

“问题是，目前我们不知道要怎么检测。我们知道要检测铅，但特定的农药呢?也许现在阻燃剂也是一个大问题。但是我们不确定是什么问题。所以我们没有没有提取孩子的大量血液样本进行测试，而是用动物血液，也就是鸽子的血液来测试各种潜在有害污染物。”

因此，与其蔑视它们是长着翅膀的老鼠，为什么不把它们看作是有翅膀的实验鼠。

2020托福听力练习：车门遥控装置安全隐患

Today's cars have loads of computer smarts built in. Like the chips that allow you, with the push of a button to unlock your car. And as new cars move down the assembly line, automakers program those functions into the car.

"They produce one car and they program a cryptographic secret in it, in order to secure it against thieves." Timo Kasper, a cryptographer and engineer at the security and IT consulting company Kasper & Oswald. "Then comes the next car on the production line and they put the same secrets into the second car. And then comes the third car on the production line and they again put the same secrets into this car. And they repeat this process for millions of cars in the world. And now millions of cars in the world share the same cryptographic secret. Of course, this secret is not so well protected anymore, because it's in every of these million cars, and in every remote control. And this is of course a typical example of how to not do it."

And yet, he says that's exactly how the Volkswagen Group did do it, for many cars manufactured in the last 20 years. Kasper and his colleagues decoded that shared cryptographic secret by studying the design and operation of chips from VW Group cars and remotes. After hacking the hardware, they were easily able to eavesdrop on and decrypt unlocking signals, clone the remote control and unlock cars. They presented the details August 12th at the USENIX Security Symposium, in Austin, Texas.

Kasper says VW is aware of the problem—and they're not alone. "This is not a VW bug but this is a red line, as we Germans say, through all the automotive industry." In fact, in the same study, they showed that another encryption system used by many other brands, including Ford, Chevy, Nissan and Mitsubishi, has a weak cryptographic algorithm—which, again, allowed the team to break into more than a dozen cars.

Bottom line? It's easier to hack into cars than many drivers might have imagined. So if you want to avoid eavesdropping, the researchers recommend simply ditching remote controls and cryptography, and just go back to the good old metal key.

现在的汽车配备了大量电脑智能系统。比如芯片，让你可以一按按钮就打开车门。新车从装配线下线时，汽车制作商就已经将这些功能编入汽车。

“汽车制造商每生产一辆汽车，就会在车内编写一个加密程序，目的是确保汽车可以防盗。”蒂莫·卡斯珀是卡斯珀和奥斯瓦尔德安全信息咨询公司的密码学家兼工程师。“然后在生产下一辆车时，他们会在这辆车上装上同样的密码系统。在生产第三辆车时，他们会再次装上同样的密码系统。他们在全球数百万辆车上重复这一过程。现在全世界有数百万辆汽车拥有同样的加密程序。当然，这个密码系统不再受到较好的保护，因为在这数百万辆车中，每辆车、每个遥控装置中都有这一密码系统。这当然是个应该避免的典型的例子。”

他表示，大众汽车就在对过去20年间生产的汽车上进行了上述操作。卡斯珀和同事们通过研究大众汽车和其遥控装置的芯片，解码了车辆共享的密码系统。在入侵硬件之后，他们很容易能够窃听和解密释放信号，克隆遥控装置解锁汽车。8月12日，他们在得克萨斯州奥斯汀举行的USENIX安全研讨会上公布了具体的信息。

卡斯珀表示。大众公司已经意识到了这个问题——意识到问题的不仅仅是大众公司。“这不是大众的漏洞，就如我们德国人描述的那样，这是整个汽车行业的红线。实际上，在同一个研究中，他们发现福特、雪弗兰、尼桑、三菱等其他品牌使用的加密算法也有纰漏，这使研究团队再一次成功解锁了10多辆汽车。

底线?入侵解锁汽车比许多司机想的更容易。如果你想避免被窃听的话，研究人员建议，只要不使用遥控和加密装置，重新使用传统的金属钥匙就可以了。

重点讲解：

1. in order to 为了;以便;目的在于;

例句：She stepped forward in order to see clearly.

她向前走了一步以便能看得更清楚。

2. eavesdrop on 偷听;窃听;

例句：German hacker claims to have cracked the encryption that protects most cellphone calls, potentially paving the way for others to eavesdrop on conversations.

一名德国黑客声称了保护大部分手机通话的加密编码，使窃听他人手机通话成为可能。

3. be aware of 注意到的;察觉到的;意识到的;

例句：John has been aware of having done something wrong.

约翰已意识到自己做错了事情。

4. break into 强行进入;闯入;

例句：They break into computers and break the phone system. Real hackers call these people crackers and want nothing to do with them.

他们入侵电脑，破坏电话系统。真正的黑客叫这些人骇客，而且不想与他们扯上边。

5. hack into (尤指为获取机密信息)侵入，非法进入(他人的计算机系统);

例句：There is no doubt that it is a criminal offence to hack into others' computers and get secret data .

毫无疑问，非法侵入他人电脑获取机密资料是刑事犯罪。