请各位记住，读GRE文章不在于读懂全文，你根本没有时间读懂。你只是 “处理 ”文章，主要线索就是论点和论据，论据大部分不用记住，只要知道在那里就是，要做快，还需要非常清楚地对于某些理论的态度，这样才可以不至于恐慌。下面我们看题目：

　　21. The passage is primarily concerned with

　　这种题目叫做主题题，一般做法是 “三出现 ”，主题词必须出现，细节，新内容不能出现。细节，指的就是把这个词从文章拿走，文章不会受影响，依然可以存在的东西。新内容，指的是文章完全没有谈到的东西。

(A) showing that intrasexual selection has a greater effect on birdsong than does intersexual selection

　　显然性间选择比性内选择重要，此选项错。

(B) contrasting the role of song complexity¹ in several species of birds（无主题词，错）

(C) describing research confirming the suspected relationship between intersexual selection and the complexity of birdsong （就是它啦）

(D) demonstrating the superiority of laboratory work over field studies in evolutionary² biology（同B）

(E) illustrating³ the effectiveness of a particular approach to experimental design in evolutionary biology( 同B)

22.The author mentions the peacock's tail in line 8 most probably in order to ( 这种题叫举例作用题，正确答案标志有两个词：illustrate 和 give an example of 所以别的选项就可以不看)

(A) cite an exception to the theory of the relationship between intrasexual selection and male competition

(B) illustrate⁴ the importance of both of the pathways that shaped the evolution of birdsong （没有谈性间选择问题，马上选D，选项业不用看，因为之可能是它）

(C) draw a distinction between competing theories of intersexual selection

(D) give an example of a feature that may have evolved through intersexual selection by female choice

(E) refute a commonly held assumption about the role of song in mate attraction

23.According to the passage, which of the following is specifically related to intrasexual selection? （问的是性内选择，还记得那个段落谈这个主题多写么，就是第一二段，）

(A) Female choice （这个就是性间选择）

(B) Territorial⁵ behavior （纯粹的性内选择，就是它）

(C) Complex song types

(D) Large song repertoires⁷

(E) Visual ornamentation

24.Which of the following, if true, would most clearly demonstrate the interaction mentioned in lines 11-13?

　　（这是最难的题目之一，叫逻辑题，也是07年10月之后的阅读重点，这种题目不用找内容对应，因为它的重点是假设某一观点成立，那一个能够最大支持 或反对这个观点，这些事实不是来自于文章，所以必须先看清楚11-13说了什么。现在做到题目看完全不迟，因为你即使刚才看了，做到这里也可能混淆，现在考了才回去看，非常直接，清晰。11-13行其实就是第二段的开头，不过请记住，GRE为了增加难度，真正的结论通常在上面一句或者下面一句，这种题目的难度就非常大了，因此，真正的要说明的观点是：The two pathways are not mutually exclusive, and we can expect to find examples that reflect their interaction.）

(A) Female larks⁸ respond similarly both to short, simple songs and to longer, more complicated songs. （没有性的吸引）

(B) Male canaries use visual ornamentation as well as elaborate song repertoires for mate attraction. （同上）

(C) Both male and female blackbirds develop elaborate visual and vocal⁹ characteristics. （同上）

(D) Male jays use songs to compete among themselves and to attract females. （性内性间都有，就是它）

(E) Male robins¹⁰ with elaborate visual ornamentation have as much reproductive success as rivals with elaborate vocal characteristics. （只有性间）

25. The passage indicates that researchers raised female cowbirds in acoustic¹¹ isolation¹² in order to （这次我们运气不那么好了，不过还是可以做，in order to前面的内容是例子，观点一般在例子的前面，把鸟儿关在隔音室里是为什么呢，当然就是为了隔开别的因素。选Ａ）

(A) eliminate confounding variables

(B) approximate field conditions

(C) measure reproductive success

(D) quantify repertoire⁶ complexity

(E) prevent early mating

26. According to the passage, the song sparrow is unlike （这就是UNLIKE出的题目，这叫做强对比，其实只要强对比出现，肯定都会出题。类似的语言标志还有：previously,by contrast等） the warbler in that the song sparrow （主语是the song sparrow，肯定选表示简单的选项）。

(A) uses songs mainly in territorial behavior （没关系）

(B) continuously composes long and complex songs （复杂）

(C) has a much larger song repertoire （复杂）

(D) repeats one song type before switching to another （重复，简单）

(E) responds aggressively to recorded songs（没关系）

27.The passage suggests that the song sparrow experiments mentioned in lines 37-43 failed to confirm the role of intersexnal selection because （失败的原因就在否定词）At first, however, researchers doing fieldwork with song sparrows found no correlation¹³ between larger repertoires and early mating, which has been shown to be one indicator¹⁴ of reproductive success

　　原因就是没有关系，答案肯定有否定词。

A) females were allowed to respond only to the song structure （没有）

(B) song sparrows are unlike other species of birds （unlike不是否定）

(C) the experiments provided no evidence that elaborate songs increased male reproductive success （就是它）

(D) the experiments included the songs of only a small number of different song sparrows （没有）

(E) the experiments duplicated some of the limitations of previous field studies （没有）