2023年公共英語考試四級(jí)臨考沖刺練習(xí)題

第頁共頁2023年公共英語考試四級(jí)臨考沖刺練習(xí)題2023年公共英語考試四級(jí)臨考沖刺練習(xí)題part1VisionHumanvisionlikethatofotherprimateshasevolvedinanarborealenviro____ent.Inthedenseplexworldofatropicalforest,itismoreimportanttoseewellthantodevelopanacutesenseofsmell.Inthecourseofevolutionmembersoftheprimatelinehaveacquiredlargeeyeswhilethesnouthasshrunktogivetheeyeanunimpededview.Ofmammalsonlyhumansandsomeprimatesenjoycolorvision.Theredflagisblacktothebull.Horsesliveinamonochromeworld.Lightvisibletohumaneyeshoweveroccupiesonlyaverynarrowbandinthewholeelectromagicspectrum.Ultravioletraysareinvisibletohumansthoughantsandhoneybeesaresensitivetothem.Humanshavenodirectperceptionofinfraredraysunliketherattlesnakewhichhasreceptorstunedintowavelengthslongerthan0.7micron.Theworldwouldlookeerilydifferentifhumaneyesweresensitivetoinfraredradiation.Theninsteadofthedarknessofnight,wewouldbeabletomoveeasilyinastrangeshadowlessworldwhereobjectsglowedwithvaryingdegreesofintensity.Buthumaneyesexcelinotherways.Theyareinfactremarkablydiscerningincolorgradation.Thecolorsensitivityofnormalhumanvisionisrarelysurpassedevenbysophisticatedtechnicaldevices.視覺人類的視覺，和其它靈長(zhǎng)目動(dòng)物的一樣，是在叢林環(huán)境中進(jìn)化出來的。在稠密、復(fù)雜的熱帶叢林里，好的視覺比靈敏的嗅覺更加重要。在進(jìn)化過程中，靈長(zhǎng)目動(dòng)物的眼睛變大，同時(shí)鼻子變小以使視野不受阻礙。在哺乳類動(dòng)物中，只有人和一些靈長(zhǎng)目動(dòng)物可以分辨顏色。紅旗在公?？磥硎呛谏模R那么生活在一個(gè)單色的世界里。然而，人眼可見的光在整個(gè)光譜中只占一個(gè)非常狹窄的頻段。人是看不到紫外線的，盡管螞蟻和蜜蜂可以感覺到。與響尾蛇不同，人也不能直接感受到紅外線。響尾蛇的感覺器可以感受波長(zhǎng)超過.7微米的光線。假如人能感受到紅外線的話，這世界看上去將非常不同，而且恐懼。到那時(shí)，將與夜的黑暗相反，我們能輕易地在一個(gè)奇異的沒有陰影的世界里走動(dòng)。任何物體都強(qiáng)弱不等地閃著光。然而，人眼在其它方面有優(yōu)越之處。事實(shí)上，人眼對(duì)顏色梯度具有非凡的分辨才能。普通人類的視覺感受色彩的靈敏程度，甚至連精細(xì)的技術(shù)裝備都很難超越。part2ChangingRolesofPublicEducationOneofthemostimportantsocialdevelopmentsthathelpedtomakepossibleashiftinthinkingabouttheroleofpubliceducationwastheeffectofthebabyboomofthe1950'sand1960'sontheschools.Inthe1920's,butespeciallyintheDepressionconditionsofthe1930's,theUnitedStatesexperiencedadecliningbirthrate——everythousandwomenagedfifteentoforty-fourgavebirthtoabout118livechildrenin1920，89.2in1930，75.8in1936,and80in1940.WiththegrowingprosperitybroughtonbytheSecondWorldWarandtheeconomicboomthatfollowedityoungpeoplemarriedandestablishedhouseholdsearlierandbegantoraiselargerfamiliesthanhadtheirpredecessorsduringtheDepression.Birthratesroseto102perthousandin1946,106.2in1950,and118in1955.Althougheconomicswasprobablythemostimportantdeterminant,itisnottheonlyexplanationforthebabyboom.Theincreasedvalueplacedontheideaofthefamilyalsohelpstoexplainthisriseinbirthrates.Thebabyboomersbeganstreamingintothefirstgradebythemid1940'sandbecameafloodby1950.Thepublicschoolsystemsuddenlyfounditselfovertaxed.Whilethenumberofschoolchildrenrosebecauseofwartimeandpostwarconditions,thesesameconditionsmadetheschoolsevenlesspreparedtocopewiththeflood.Thewartimeeconomymeantthatfewnewschoolswerebuiltbetween1940and1945.Moreover,duringthewarandintheboomtimesthatfollowed,largenumbersofteacherslefttheirprofessionforbetter-payingjobselsewhereintheeconomy.Thereforeinthe1950'sand1960's,thebabyboomhitanantiquatedandinadequateschoolsystem.Consequently,the“custodialrhetoric”ofthe1930'sandearly1940'snolongermadesensethatis,keepingyouthsagedsixteenandolderoutofthelabormarketbykeepingtheminschoolcouldnolongerbeahighpriorityforaninstitutionunabletofindspaceandstafftoteachyoungerchildrenagedfivetosixteen.Withthebabyboom,thefocusofeducatorsandoflaymeninterestedineducationinevitablyturnedtowardthelowergradesandbacktobasicacademicskillsanddiscipline.Thesystemnolongerhadmuchinterestinofferingnontraditional,new,andextraservicestoolderyouths.公共教育的角色變化一項(xiàng)重要的、有可能促使人們對(duì)公共教育的角色的看法發(fā)生轉(zhuǎn)變的社會(huì)開展是本世紀(jì)五六十年代的生育頂峰對(duì)學(xué)校的影響。在20年代，尤其是在30年代后的大蕭條中，美國經(jīng)歷了一次出生率的下降——1920年每千名年齡在15歲至45歲的'婦女生下大約118個(gè)存活嬰兒，1930年89.2個(gè)，1936年75.8個(gè)，1940年80個(gè)。隨著二戰(zhàn)帶來的持續(xù)繁榮以及隨之而來的經(jīng)濟(jì)增長(zhǎng)，年輕人比大蕭條中的同齡人更早地結(jié)婚成家，而且比前輩養(yǎng)育更大的家庭。1946年出生率上升到102%，1950年達(dá)106%，1955年達(dá)118%。對(duì)于生育頂峰，經(jīng)濟(jì)有可能是最重要的決定因素，但它并不是唯一的解釋。不斷受到重視的家庭觀念也有助于解釋出生率的上升。到40年代中期為止，這些生育頂峰出生的孩子們開場(chǎng)不斷地進(jìn)入小學(xué)一年級(jí)。到了1950年，就形成了一股洪流。公共教育系統(tǒng)突然感到不堪重負(fù)了。由于戰(zhàn)時(shí)和戰(zhàn)后的狀況，使得學(xué)齡兒童人數(shù)增加，這些狀況使得學(xué)校面對(duì)這股洪流更加措手不及。戰(zhàn)時(shí)經(jīng)濟(jì)意味著在1940年到1950年間幾乎沒有建立新學(xué)校。而且，在戰(zhàn)時(shí)和隨后的經(jīng)濟(jì)增長(zhǎng)時(shí)期，大量的老師分開崗位去別處從事報(bào)酬更為優(yōu)厚的