As Gilbert White，Darwin ， and others observed long ago， all species appear to have theinnate capacity to increase their numbers from generation to generation. The task forecologistsis to untangle the environmentaand biologicalfactorsthat hold this intrinsiccapacity for population growth in check over the long run. The great variety of dynamicbehaviorsexhibitedby differentpopulationmakes thistaskmore difficult：sompopulations remain roughly constant from year to year; others exhibit regular cycles ofabundance and scarcity; still others vary wildly， with outbreaks and crashes that arein some cases plainly correlated with the weather， and in other cases not.To impose some order on this kaleidoscopeof patterns ， one school of thought proposesdividing populations into two groups. These ecologists posit that the relatively steadypopulations havedensity-dependent growth parameters; that is， rates ofbirth ， death ，and migrationwhich depend strongly on population density. The highly varying populationshave density-independent growth parameters， with vital rates buffeted by environmentalevents ;these rates fluctuate in a way that is wholly independent of population density.This dichotomy has its uses， but it can cause problems if taken too literally. Forone thing ， no population can be driven entirely by density-independent factors all thetime. No matter how severely or unpredictably birth， death ， and migration rates may befluctuatingaround theirlong-termaverages ， ifthere were no density-dependenteffects ，the populationwould ， in the long run ， eitherincrease or decrease without bound (barringa miracle by which gains and losses canceled exactly)。 Put another way， it may be thaton average 99 percent of all deaths in a populationarise from density-independentcauses ，and only one percent from factors varying with density.The factorsmaking up the one percentmay seem unimportant， and their cause may be correspondingly hard to determine. Yet，whether recognized or not， they will usually determine the long-term average populationdensity.In order to understand the nature of theecologist ’s investigation， we may think ofthe density-dependent effectson growth parameters as the signal ecologists are trying toisolateand interpret， one that tends to make the population increase from relativelylowvalues or decrease from relatively high ones， while the density-independent effects actto produce noise in the populationdynamics.For populationsthatremain relativelyconstant ， or that oscillate around repeated cycles， the signal can be fairly easilycharacterized and its effects described， even though the causative biological mechanismmay remain unknown. For irregularly fluctuating populations， we are likely to have toofew observations to have any hope of extracting the signal from the overwhelming noise.But it now seems clear that all populationsare regulatedby a mixture of density-dependentand density-independent effects in varying proportions.
1. The author of the text is primarily concerned with
[A] Discussing two categories of factorsthat controlpopulationgrowth and assessingtheir relative importance.
[B] Describinghow growth ratesin naturalpopulationsfluctuateover time andexplaining why these changes occur.
[C] Proposing a hypothesisconcerning population size and suggesting ways to test it.
[D] Posing a fundamental question about environmentalfactorsin populationgrowth andpresenting some currently accepted answer.
2. It can be inferred from the text that the author considers the dichotomy discussedto be
[A] Applicable only to erratically fluctuating populations.
[B] instrumental， but only if its limitations are recognized.
[C] Dangerously misleading in most circumstances.
[D] A complete and sufficient way to account for observed phenomena.
3.to the text ， allof the followingbehaviors have been exhibitedby differentpopulations EXCEPT
[A] Roughly constant population levels from year to year.
[B] Regular cycles of increases and decreases in numbers.
[C] Erratic increases in numbers correlated with the weather.
[D] Unchecked increases in numbers over many generations.
4. The discussion concerning population in the third paragraph serves primarily to
[A] Demonstrate the difficultiesecologistsface in studying density-dependentfactorslimiting population growth.
[B] Advocate more rigorous study of density-dependent factors in population growth.
[C] Prove that the death rates of any populationare never entirelydensity-independent.
[D] underline the importance of even small density-dependent factors in regulatinglong-term population densities.
5. In the text， the author does all of the following EXCEPT
[A] Cite the views of other biologists.
[B] Define a basic problem that the text addresses.
[C] Present conceptual categories used by other biologists.
[D] Describe the results of a particular study.
ABDDD
1.「答案」A
「考点解析」这是一道中心主旨题。本文的中心主旨句在第三段的首句。如果考生能够抓住第三段的首句就等于抓住了整篇文章的论述结构。该句中的“dichotomy”(两分法)就是正确选项中的“twocategories”。考生在解题时应首先抓住每篇文章的中心主旨句，因为这决定了对全文
结构的认识以及对原文整体的把握。
2.「答案」B
「考点解析」这是一道细节推导题。根据题干中的“dichotomy”可将本题的答案信息来源迅速确定在第二段的首句。如果考生能够正确理解该句中“but”一词前后的内容，就可以找出本题的正确选项B.考生在解题时一定要正确理解原文所传达的含义，即进行正确的细节推导。
3.「答案」D
「考点解析」这是一道审题定位与中心主旨题。根据本题题干中的“differentpopulations”可将本题的答案信息来源确定在首段的第一句，因为该句中的“allspecies”实际上指的就是题干中的“differentpopulations”。从第一段的首句入手并且仔细阅读首段的第二句，就可以找出本题的正确选项D，因为该选项所传达的信息与原文第一段第一、二句所传达的信息不一致。考生在解题时一定要学会迅速审题定位的能力。
4.「答案」D
「考点解析」本题是一道归纳推导题。题干已明确指出该题的答案信息来源在第三段。第三段主要陈述“density-dependentfactors”的作用，通过仔细阅读第三段，尤其是第三段的最后三句话，考生可以得知本文作者在第三段是在强调“density-dependentfactors”的作用。可D是本题的正确选项。考生在理解原文时一定要注意掌握归纳推导的能力。
5.「答案」D
「考点解析」本题是一道写作手法题。这是一道比较难的题目，旨在考察考生的语言功底。本文作者在论述自己的观点时运用了各种写作手段。选项A、B、C中所涉及的内容分别在第一段、第三段和第二段中出现。考生一定要提高对原文各种写作手段的认识。
-Wehaven’theardfromJaneforalongtime.
-Whatdoyousuppose_____toher?
In some countries where racial prejudice is acute, violence has so come to be taken for granted as a means of solving differences, that it is not even questioned. There are countries where the white man imposes his rule by brute force; there are countries where the black man protests by setting fire to cities and by looting and pillaging. Important people on both sides, who would in other respects appear to be reasonable men, get up and calmly argue in favor of violence – as if it were a legitimate solution, like any other. What is really frightening, what really fills you with despair, is the realization that when it comes to the crunch, we have made no actual progress at all. We may wear collars and ties instead of war-paint, but our instincts remain basically unchanged. The whole of the recorded history of the human race, that tedious documentation of violence, has taught us absolutely nothing. We have still not learnt that violence never solves a problem but makes it more acute. The sheer horror, the bloodshed, the suffering mean nothing. No solution ever comes to light the morning after when we dismally contemplate the smoking ruins and wonder what hit us. The truly reasonable men who know where the solutions lie are finding it harder and herder to get a hearing. They are despised, mistrusted and even persecuted by their own kind because they advocate such apparently outrageous things as law enforcement. If half the energy that goes into violent acts were put to good use, if our efforts were directed at cleaning up the slums and ghettos, at improving living-standards and providing education and employment for all, we would have gone a long way to arriving at a solution. Our strength is sapped by having to mop up the mess that violence leaves in its wake. In a well-directed effort, it would not be impossible to fulfill the ideals of a stable social programme. The benefits that can be derived from constructive solutions are everywhere apparent in the world around us. Genuine and lasting solutions are always possible, providing we work within the framework of the law. Before we can even begin to contemplate peaceful co-existence between the races, we must appreciate each other's problems. And to do this, we must learn about them: it is a simple exercise in communication, in exchanging information. "Talk, talk, talk," the advocates of violence say, "all you ever do is talk, and we are none the wiser." It's rather like the story of the famous barrister who painstakingly explained his case to the judge. After listening to a lengthy argument the judge complained that after all this talk, he was none the wiser. "Possible, my lord," the barrister replied, "none the wiser, but surely far better informed." Knowledge is the necessary prerequisite to wisdom: the knowledge that violence creates the evils it pretends to solve.
1. What is the best title for this passage?
[A] Advocating Violence.
[B] Violence Can Do Nothing to Diminish Race Prejudice.
[C] Important People on Both Sides See Violence As a Legitimate Solution.
[D] The Instincts of Human Race Are Thirsty for Violence.
2. Recorded history has taught us
[A] violence never solves anything. [B] nothing. [C] the bloodshed means nothing. [D]everything.
3. It can be inferred that truly reasonable men
[A] can't get a hearing.
[B] are looked down upon.
[C] are persecuted.
[D] Have difficulty in
advocating law enforcement.
4. "He was none the wiser" means
[A] he was not at all wise in listening.
[B] He was not at all wiser than nothing before.
[C] He gains nothing after listening.
[D] He makes no sense of the argument.
5. According the author the best way to solve race prejudice is
[A] law enforcement. [B] knowledge. [C] nonviolence. [D] Mopping up the violent mess.
- We haven’t heard from Jane for a long time.
-What do you suppose_____ to her?
Thecaris_____expensive_____hecan’tbuyit.
—Are you hungry now?
—_______. I have just had two bowls of rice.
