托福听力高频主旨题如何保证得分?实用解题技巧精讲
做好托福听力主旨题无关词汇量从开头找线索
关于托福听力主旨题的解题技巧，考生应该首先注意的是这两种题型与大家词汇量的多少无关。也就是说，词汇量即使很少也不会给这两种题型的解题造成障碍。考生真正要做的是首先听准开头;特别是开头句型，之后找出对话目的;如果开头没有把握准，那么要注意全文重复词汇;最后要听准关键词并对实义词(名词、动词、形容词)足够敏感。
托福听力对话和讲座如何听准开头段?
那么，考生应该如何听准托福听力的开头段呢?大家要注意的是，在conversation和lecture的开头中，有的文章会出现寒暄部分。
比如，在conversation中两个说话者的在开头部分都会出现互相问好的寒暄语：
e.g.1 A : Hey, how is everything going?
B: Well, everything is going fine.
e.g.2 A: Hi, are you Paula?
B: Oh, hi, Jim. Nice to see you!
在这些寒暄之后说话人A说Do you need some tutoring in English? 说话人B说：yes, I am taking English composition and my English is not very good. 这才是文章的真正内容，也就是文章的主旨。所以选项的相应部分选择的是：She needs a tutoring appointment!
在lecture中，有时教授上来不会直接切入正题，而是先会寒暄几句。
例1： 有个教授上来先说I am sorry that I didn’t bring your paper, and it took longer to grade than I thought. So I will bring you the paper next class. Today, I want to continue our topic about Renaissance. 所以 “I am sorry that I didn’t bring your paper, and it took longer to grade than I thought. So I will bring you the paper next class.” 这句话都是在说与文章主旨无关紧要的话。而真正与文章主旨有关的是以today开头的这句话!所以，显而易见，这篇文章的主要内容就是文艺复兴Renaissance。
例2： In the last class, we discussed the Jazz music history. But today, I am going to talk about the development of the jazz music. 那么很显然，In the last class, we discussed the Jazz music history.这是上节课讲的内容。在强转折but之后，老师紧接着说I am going to talk about the development of the jazz music. 那么，文章的主旨也就很明确了。
2020托福听力练习：疟蚊喜欢牛而不是人类
As you've probably experienced firsthand, some mosquito species have a real taste for warm, human blood. So much so that if you raise them on in the lab, they'll accept no substitute.
"Fortunately, I don't get major reactions at all." Brad Main is a mosquito geneticist at U.C. Davis… and part-time mosquito meal provider. "So it's not too bad for me. But some people in the lab are itching pretty bad when they have hundreds of mosquito bites on their arms."
Out in the wild, some species are less picky. Take Anopheles arabiensis, common in East Africa. They'll feed on cattle, dogs, goats, pigs, people—wherever they can find a warm meal. But what Main and his colleagues wanted to know was whether the bloodsuckers' choice of victim might be genetically determined. So they sequenced the genomes of 48 arabiensis mosquitoes from Tanzania which had fed on either humans or cows.
And they found that bugs with cow blood in their bellies had one partially rearranged chromosome, compared to those who'd snacked on human blood… which could explain the preferences in meal choices. The study is in the journal PLoS Genetics.
If that genetic switch really does make cows more attractive than we are to mosquitoes, in theory we could genetically engineer them to steer clear of people. And their cow victims don't get human malaria. "It's a case of knowing your enemy. And so the better we know these mosquitoes, I think the more equipped we're going to be able to control them."
正如大家可能亲身经历过的那样，一些蚊子喜欢温暖的人类血液。以至于如果你把它们养在实验室里，它们会拒绝替代品。
“幸运的是，我完全没有感到明显的反应。” 布拉德·曼恩是加州大学戴维斯分校的蚊子遗传学家和兼职蚊子食物供应商。“所以它对我来说不是太坏。但当实验室里有数百只蚊子在叮咬他们的胳膊时，一些人会感觉非常痒。”
在野外，一些物种没那么挑剔。以东非常见的阿拉伯按蚊为例。它们以牛、狗、山羊、猪以及人类的血为食，它们在任何地方都能找到温暖的一餐。但曼恩和他的同事们想知道的是，这些吸血动物选择的受害者是否是由基因决定的。所以他们在坦桑尼亚收集了48只以人或牛血液为食的阿拉伯按蚊，并对它们进行了基因组排序检测。
他们发现，与吸食人类血液的蚊子相比，那些吸食牛血的蚊子的腹部有一部分细菌染色体重排，这可以解释膳食的选择偏好。这一研究结果发表在《公共科学图书馆遗传学》期刊上。
如果说这种基因转变真能使牛比我们对蚊子更具吸引力，那在理论上我们可以通过基因工程来使蚊子远离人类。而牛也不会感染人疟。“这是一个了解敌人的例子。我们越是了解这些蚊子，我们就越能更好地控制它们。”
重点讲解：
1. have a taste for 喜欢;偏好;
例句：She has a taste for classic music.
她喜欢古典音乐。
2. compared to 与…相比;和…比起来;
例句：Compared to the noisy cities, he preferred the quiet country life.
比起喧闹的大城市，他更喜欢宁静的乡村生活。
3. in theory 从理论上说;照理说;
例句：Your plan sounds fine in theory, but I don't know if it'll work in practice.
你的计划理论上不错,但我不知道实际上是否行得通。
4. steer clear of 避开;躲避;绕开;
例句：I think a lot of people, women in particular, steer clear of these sensitive issues.
我认为很多人，特别是女性，都会回避这些敏感问题。
2020托福听力练习：醉酒者在酒鬼身边会感觉清醒
Volunteers in scientific studies sometimes get compensated. The payment can be cash, a gift card or something almost worthless: "It's amazing what people will do for a lollipop, when they've had a few drinks."
Simon Moore is a professor of public health research at Cardiff University in the U.K. And the lollipops were for people who agreed to blow into a breathalyzer, while out on a Friday or Saturday night in Wales—more than 1,800 people agreed to the exchange. The scores covered a wide range of alcohol intake. "So that would go from zero upwards. I think one of the largest scores we had was 120, which is a near death experience."
The researchers also gave a subset of volunteers a short survey about drinking habits and health risks. Questions like: "How drunk are you right now?" and "How extreme has your drinking been tonight?" And they found that even very drunk respondents felt relatively more sober, if they were surrounded by even drunker people. In other words: our perception of intoxication—and its risks—is relative.
"So this is the point, as you change context, perceptions will change, although the absolute level of alcohol in their system doesn't change." The study is in the journal BMC Public Health.
Moore says one way to use this finding is for better city zoning. "In the United Kingdom for example there's been a big push to put more premises that sell alcohol in the same district, in the same area. And what this does is create a concentration of drinkers. So what we might argue from this is, well let's try to break that up a little bit." Have a mix of bars, restaurants, cafes and cinemas, so drinkers will be around relatively sober people, too, instead of fellow inebriates. Which might encourage drinkers to nurse their drinks…and thus avoid the ER.
参加科学研究的志愿者们有时会得到报酬。这些报酬可能是现金、礼物卡、或是没有什么价值的东西：令人惊奇的是人们在喝了几杯酒为了一根棒棒糖所做的事。
西蒙·穆尔是英国卡迪夫大学公共健康研究教授。这些棒棒糖是为同意对酒精含量测试器吹气的人准备的，这些人是会于周五、周六晚上在威尔士享受夜生活的人，最后有超过1800人同意参加这种交易。测试结果是这些人的酒精摄入量分布较广。“所以，那会从零开始向上增长。我想我们得到的最高分值是120，这是一次濒死体验。”
研究人员还对小部分志愿者进行了饮酒习惯以及健康风险的简短调查。问题如下：“你现在喝醉了吗?你今天晚上喝到极限了吗?”结果发现，即使喝得烂醉的受访者也感觉比较清醒，当然前提是他们周围还有更醉的人。换言之，我们的醉酒知觉和醉酒的风险是相关的。
所以，这就是关键了，当环境改变时，我们的知觉也会改变，但其实体内酒精的真实含量并没有变化。该研究结果发表在《英国医学委员会公共健康》期刊上。
穆尔表示，可以将此研究结果用于改善城市区域的划分。“比如，英国已经在大力推行让更多售酒店铺集中在同一个街区和同一个地区。这样做是为了让饮酒者集中起来。我们也许会对此提出质疑，我们应尽量对这种情况作出一点抵制。”如果有更多的酒吧、饭店、咖啡店以及电影院这样的混合商区，那么饮酒的人周围也会有相对清醒的人，而不是同样烂醉的人。这也许能鼓励饮酒的人关注自己的饮酒习惯，这样就可以避免被送到急诊室。
重点讲解：
1. in other words 换言之;换句话说;也就是说;
例句：In other words, we had better take sufficient recreation to relax after work.
换句话说，我们最好工作后，消遣消遣来轻松一下。
2. break up (使)分裂;(被)拆分;(使)破碎;
例句：Police tried to break up the gang.
警察试图瓦解黑帮。
3. instead of 代替…;而不是…;
例句：He chose the gun instead of the cap and gown.
他选择当兵而不是上大学。
4. encourage sb. to do sth. 鼓励;激励;
例句：If he should fail, we would encourage him to try again.
万一他失败，我们就鼓励他再试一次。
