00015自考英语(二)考纲精练试卷(二)及答案.pdf

英语(二)自学教程

标准预测试卷·考纲精练(二)

第一部分:阅读判断

ADogsDilemma

Findingababysitterwhileyougoouttoworkis，forexample，an

InconvenIence.Forthe

Africanwilddog，oneofthecontinentsmostendangered

carnivores，itsamatteroflifeanddeath.

Newresearchshowsthatoncepacksfallbelowacertainsize，thereare

notenoughanimalstobothhuntfoodandstayathomeprotectingthe

young.

TheMricanwilddoghasdec.lineddrasticallyoverthepastcentury.

Habitualloss,persecutionandunexplainedoutbreaksofdiseasehaveall

beenblamed.Only3，000.to5，000animalsremain，andthespeciesis

expectedtogoextinctwithindecadesifthetrendcontinues.

Otherlargecarnivoressuchasthespottedhyenafacesimilar

pressures，yetarenotdeclining.NowFranckCourchampofCambridge

Universityhasfoundareasonwhy.Thedogsweaknessliesinitssocial

organisation.

Withineachpackofupto20adultsandpups，onlythedominant

maleand守femalebreed.

Theremaininganimalshelpraisethepups，cooperatingtohunt

preyanddefendthekillfromothercarmvores.

Becausepupscantkeepuponahunt，largepacksleaveanadult

behindtoprotectthemfrom

predators，whichincludelionsandhyenas.Butleavinga

babysitteralsocarriescosts.Asmallerhuntingpartyislessableto

tacklelargepreyandtodefendthekill.Thereisalsoonelessstomach

inwhichtocarryfoodbacktotheden，andonemoremouthtofeedwhen

theygetthere.

Courchampinvestigatedthisawkwardtrade-offbymodellinghowthe

costsofababysitterchangewithdecreasingpacksize.Thisshowedthat

packsofmorethanfiveadultsshouldbeabletofeedallthepupsand

stillspareababysitter.Butwithsmallerpacks