天文学一直以来就是雅思各项单科考试中难度颇高的命题，无论是今年1月份雅思口语爆出有关sky和star的冷门话题，还是剑桥雅思阅读中有关外星生命的文章，无一不令考生高山仰止、望而却步。本文就剑桥真题9中的“Is Anybody Out There?(探究外星生命)”一文的选段进行分析，分析如何运用skimming(略读法)这一基本阅读法来把握段落主旨，学习并借鉴议论文地道的写作思路。

　　原文重现：

　　Even when we make these assumptions, our understanding of other life forms is still severely limited. We do not even know, for example, how many stars have planets, and we certainly do not know how likely it is that life will arise naturally,?given the right conditions. However, when we look at the 100 billion stars in our galaxy [the Milky Way], and 100 billion galaxies in the observable Universe, it seems?inconceivable that at least one of these planets does not have a life form on it; in fact, the best educated guess we can make, using the little that we do know about the conditions for carbon-based life, leads us to estimate that perhaps one in 100,000 stars might have a life-bearing planet orbiting it. That means that our nearest neighbors are perhaps 1000 light years away, which is almost next door in astronomical terms.

　　翻译：

　　即便我们做出了上述假设，我们有关外星生命的了解依然相当有限。比如，我们甚至不知道有多少恒星是有行星围绕的，我们也不知道在适合条件下生命发源的可能性如何。然而，当我们遥望我们的银河系中1000亿颗恒星和其他1000亿个银河系的时候，其中某个行星上存在生命的想法并非天方夜谭。

　　事实上，就已知的碳元素作为生命基本元素的常识不难令我们大胆揣测，或许十万颗恒星中就有一颗恒星拥有具备生命体的行星围绕着。而这意味着距离我们地球1000光年之遥的那颗具备生命体的行星，站在天文学角度来说其实是我们最近的邻邦。

　　原文逻辑结构分析：

　　此段是典型的议论文写作思路：论点1——举例——转折——论点2——论证——结论。首句Even when we make these assumptions, our understanding of other life forms is still severely limited.看似提出论点，其实是作者抛砖引玉的一个绣球，并非本段真正主旨句，考生可以留心，但不能依据此句去选heading。第二句中的for example表明此句是举例，可以略去不看。第三句中的however转折句峰回路转，作者真正的写作意图开始显露端倪。

　　果不其然，it seems?inconceivable that at least one of these planets does not have a life form on it;一句以及结尾处的分号将作者的论证过程演绎得深入浅出、通俗易懂。最后一句总结句才是本段落真正的主旨句，论证严密、完美落幕。

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