分析听力讲座中的直线结构文章

此类文章通常都是介绍一位名人或是一个物品。介绍人的话，会依次介绍他（她）的特点、代表作、生平、生平对我们的启发等；介绍物品的话，会逐步介绍该物品的用途、特色、如何被发明创造或是被考古挖掘出来的，以及对它的发扬光大、保护保存等问题的探讨。同样是以某篇讲座为例，该文章是一篇艺术类讲座，文章开篇就开门见山介绍了本文主题：

All right, let’scontinue our discussion of portrait artists (portraitist) and portraiture. A great example of that, that vision in portraiture, is Cecilia Beaux.’（著名的肖像画家塞西莉亚·博斯）

随后介绍了作为一名女性，她在当时的成就是十分惊人的：

‘She really stood outback in the 1800s. And today, she is still considered one of the greatest portrait painters of her time, male or female.’以及她画作的风格，“Those portraits also reflect the kind of subjects that Beaux tended to use, which were mostly women and children.”（通常主角都是女性和孩子们）

然后再重点介绍了她的一幅作品：

‘The Dream’，‘So let’s look at one of her portraits now. This painting is called The Dreamer.’

通过分析这幅画作让听者了解了Beaux的特点：

‘But what strikes me is the contrasting colors, the white dress and the dark background.’（色彩对比鲜明），‘The background behind the woman is pretty vague. Like, maybe there is no real context. The unclear background definitely contributes to that dreaminess.’（模糊的背景更加突出了画作的主题）

最后再点睛式地强调一下Beaux的独特之处：

‘Beaux used some impressionist techniques and share much of their philosophy, but her style, it was all her own.’（虽借鉴了印象派技巧但又自成一派）

全文一气呵成，娓娓道来，让听者对于这位女性肖像画家有了初步但又不失全面的了解。

此类文章通常都是介绍一个理论，它的提出背景，支持者和反对者对此的论证和批判，它的前景等，或者说是介绍当前面临的一个问题或已经存在的某一现象，社会是如何看待的，如何去解决的，展望一下未来等。再以一篇具体的文章为例，该文章是一篇生物类讲座，在文章开头教授就介绍了有一位生物学家提出了自己的一个假设，称之为高斯假设：

‘A biologist named G.F.Gause first proposed what's known as "Gause's hypothesis".’

随后具体介绍了该假设的内容：

‘Whenever you've got two similar species competing for the exact same limited resources, one of them will have some sort of advantage, however slight that'll eventually enable this species to dominate and ultimately exclude the other one, even cause it to become extinct.’（两个物种竞争同一资源时最终总有一方是强者，甚至会使得另一方灭绝）

到此，文章算是很好地引入了这一假说，让听者对此有一个较为深刻的认识。接着就开始阐述批评者对此假说的态度了：

‘It works in simple lab experiments where you have just two competing species in a controlled environment, but the hypothesis falls apart when applied to natural ecosystems where things are more complex.’（只适用于简单的实验室环境，但不适用于复杂的自然环境）

面对质疑，教授随即用一个wobbler鸟的例子来反驳此批评：

‘But if you observe these birds more closely, the wobbler species are not really competing with one another for the exact same food at the exact same time’（这五种wobbler鸟并不是在竞争同一种资源，而是互相协作以共同生存）

以此来表明高斯假设并没有被推翻，在大自然中也同样是适用的。文章环环相扣，引出理论、提出质疑、表明证据、驳斥质疑四个部分逐步深入，在逻辑上是十分紧密的。