在六级听力讲座部分一定要要重视首段的功效，因为其往往点出一篇文章的主题，为这篇文章的走势方向打下基调。当是面对篇幅较长、题材多样、内容丰富的六级的讲座，只理解开篇或许能够帮助大家拿到一部分分数，要想取得更高分数，那么就需要一些辅助的招数，教给大家一个被人们忽略却非常重要的技巧——预测。
有不少同学把重点放在听文章上，听耳边出现的每一个单词，试图将耳边的音符译成汉语，结果是不尽人意，后面的内容很可能不知所云，内心也是异常焦躁。其实，就像日常生活中我们同别人交流常常会考虑对方接下来会说些什么一样，我们在英文听力中，在把握文章主题，抓住段落中的关键词和核心概念后，也应该迅速激活自己在该话题领域的相关知识，对可能听到的内容进行合理预测。能够运用预测的技巧合理推测后文内容从而做到和作者的思想交流，对于我们掌握整篇文章起着事半功倍的效用，所以大家一定要重视预测这一听力技巧。
现在我们来听一篇六级听力讲座题：
Now listen to the following recording and answer questions 23 to 25
Now listen to the following recording and answer questions 23 to 25
23
A.The former is helpful while the latter is harmful.
B.The former can be avoided while the latter cannot.
C.The former causes more harm than the latter.
D.The former is natural while the latter is not.
24
A.Large areas of forests are felled.
B.The world population keeps increasing.
C.People create things that release extra heat.
D.There are too many cars that bum gas.
25
A.The polar ice caps and glaciers will melt.
B.More animals will have to find new habitats.
C.The price of gas will keep soaring.
D.There will be more earthquakes.
原文：
Many people may not realize it, but the greenhouseeffect and global warming are totally differentthings. The greenhouse effect is something thathappens with all celestial bodies — planets, moons,and suchthat have an atmosphere. Anyway, backto the greenhouse effect. The greenhouse effect isa process that happens when the sun's heat entersEarth's atmosphere. The sun's rays warm the earth, and the atmosphere keeps the heat in,just like a greenhouse. It's a very natural thing, and in most cases, the planet system knowshow to balance itself out. Anyway, like I said, it's a pretty natural process.
Now all this gets messed up when humans, um, add stuff to Earth's atmosphere. That's whenglobal warming, which is not a natural process, happens. See, what happens is that peoplecreate, um, things that create extra heat. For example, cars. We drive cars all the time. So wedrive our cars, and our cars bum gas, and this exhaust is pretty hot. And the atmospherekeeps this heat around the planet. Plus, all of our machinery and our factories and stuff, theyall produce heat. So all this stuff creates what scientists are calling global warming. Earth'ssurface and atmosphere just keep getting hotter.
Now global warming has many negative effects, but I think one of the biggest problems withglobal warming is the melting of polar ice caps and glaciers. See, our planet has huge chunksof ice at both of its poles. And when global warming happens, um, the overall temperature ofthe planet increases. And what this does is it makes polar ice melt. So when ice melts, it turnsinto water, which goes into our oceans. And that causes the level of water to rise. And thiscould also cause major flooding.
问题：
Question 23. What's the difference between greenhouse effect and global warming?
Question 24. According to the speaker, why does global warming happen?
Question 25. What's the speaker's biggest concern with global warming?
原文释义：
很多人或许没有意识到，但是温室效应和全球变暖是两种完全不同的事。温室效应是所有有大气层的天体都会出现的现象，比如行星、月球，等等。不管怎样，继续说温室效应。当太阳的热量进入地球大气层时，就会出现温室效应。太阳光使地表暖和起来，而大气层将热量保存起来，就像个温室一样。温室效应是一个十分自然的过程，多数情况下，地球系统自有办法保持平衡。总之，就像我说的，它是一个很自然的过程。
当人类在大气中增加了很多物质时，所有的这一切就变糟糕了。那时候就会出现很不自然的过程——全球变暖。全球变暖是由于人们制造了很多排放多余热量的事物。比如，汽车。我们一直都在开车。我们开车，车会产生气体，而这些气体温度较高。大气层将这些热量保存在地球周围。另外，我们的机器、工厂等等，都会产生热量。所有这些东西就造成了科学家所说的全球变暖。地球表面和大气层都变得越来越暖。
现在全球变暖有很多负面影响，但是我觉得全球变暖最大的问题之一就是极地冰盖和冰川的融化。我们的地球在两极地区都有大量的冰川覆盖。出现全球变暖以后，地球的整体温度上升。这带来的影响就是极地冰雪融化。那么冰雪融化时，就会变成水，流入海洋。这会使海平面上升。也会造成严重洪灾。
问题释义：
问题23 温室效应和全球变暖的区别是什么?
问题24 根据发言人，为什么会出现全球变暖?
问题25 发言人对全球变暖最大的担忧是什么?
参考答案：
【小题23】D
【小题24】C
【小题25】A
习题解析：
【小题23】听力原文在对温室效应进行解释说明之后总结说Anyway, like I said, it's a pretty natural process. 指出温室效应是一个十分自然的过程。随后说到人类在大气中增加了很多物质时，所有的这一切就变糟糕了，并紧接着提到That's when global warming, which is not a natural process, happens.由此可见，全球变暖不是自然过程，而是人类使然，因此D项表述正确，故选D。
【小题24】听力原文中在说到全球变暖并非自然过程之后，提到See, what happens is that people create, um, things that create extra heat.由此可知，全球变暖是由于人们制造了很多排放多余热量的事物，故选C。A、B两项在听力原文中并未提及，D项中提到了消耗汽油的汽车，但这只是造成全球变暖的一个因素，并不能概括所有因素，故排除。
【小题25】听力原文中提到Now global warming has many negative effects, but I think one of the biggest problems with global warming is the melting of polar ice caps and glaciers.指出在演讲者看来，全球变暖的最大问题在于极地冰雪融化，因而A项表述正确，故选A。其他几项在听力原文中并未提及，均排除。
