本文格式為Word版，下載可任意編輯——2022公共英語五級(jí)閱讀文章《沙漠中的植物》對(duì)于備考公共英語五級(jí)的考生來說，閱讀理解是其中的難點(diǎn)之一?？忌缦氆@得對(duì)比高的閱讀理解分?jǐn)?shù)是需要花費(fèi)不少的精力去練習(xí)的。下面，我為大家送上一篇2022公共英語五級(jí)閱讀文章，夢(mèng)想對(duì)大家有所扶助。

閱讀原文：

Somecacti,likethesaguaro,growtotreesize,buttruetreesneedmoremoisturethanmostdesertenvironmentscansupply,sotheyarescarceondeserts.Closetostreambeds,cottonwoodscansometimesbefound.Thoughthesestreamsaredrymostoftheyear,waterflowstherelongestandisusuallyavailablefairlyclosetothesurface.Elsewhere,treesmustsendtaprootsdeepintothehardbakeddesertsoiltodrawonundergroundwater.Perhapsthemostwidespreadfamilyoftreesontheworldsdesertsistheacacia,whosetaprootsdrilldownasfaras25feet7.5meters.ThemesquitecommononNorthAmericandesertsinbothtreeandshrubforms,doesnotbegintogrowabovegrounduntilitsrootsystemiscompletelydeveloped,ensuringtheplantasupplyofmoisture.Therootsofshrubsandtreeshelptoholdthedesertsoilinplace.Theirstalksandbranchesalsoactasscreenstokeepthewindfromsweepinggreatdriftsofsandalongthesurface.Theseservicesarevitalifadesertistosupportlife.Scientistsestimatethatadesertneedsyearroundplantcoverover20to40percentofitssurface.Ifshrubsaretoofarapart-separatedbyadistancegreaterthanfivetimestheirheight-soilaroundthemislikelytoblowaway.Withouttheshelterofestablishedshrubs,newseedlingswillhavedifficultyingettingastart.Ontheotherhand,plantsthataretooclosetogethermaycompeteforundergroundmoisture.Toprotectthemselvesfromthiscompetitionsomeshrubsgiveoffasubstancethatkillsyoungplantsthatsprouttooclosetothem.Inadditiontoafewvarietiesoftreesandtoughshrubs,mostdesertshavegrasses,herbs,andotherannualplants.Thesedonotcompeteformoisturewiththelongerlivedgrowth.Theyspringupquicklyafterrains,whenthesurfaceismoist.Then,forabrieftime,thedesertcanbeliterallycarpetedwithcolor.Almostasquicklyastheyappeared,thesesmallplantsdieaway.Buttheyhavedevelopedspecialwaysofensuringthelifeofanothergenerationwhenrainscomeagain.

參考譯文：

一些仙人掌，如撒瓜羅，能長到象樹那么高。但真正的樹卻需要比大多數(shù)沙漠所能供給的更多的水份，所以樹在沙漠里是鮮見的。在小溪河床鄰近，有時(shí)能察覺三角葉楊。盡管一年的大多數(shù)時(shí)間里這些小溪都是枯竭的，那里卻是水流得時(shí)間最長的地方而且水份相當(dāng)靠近地表。其它地方樹木的主根務(wù)必深入受炙烤而堅(jiān)硬的沙漠底部的土壤以吸取地下水。在沙漠里分布最廣的樹或許是刺魏，其主根能深達(dá)25英尺合75米。牧豆樹屬植物不管是喬木和灌木，在北美沙漠中往往可見，在它根部系統(tǒng)完全生長興隆到能保證供給充沛的水分時(shí)才長出地面。灌木和樹的根有助于固定沙漠中的土壤，它們的莖和樹枝同時(shí)起屏障的作用，防止風(fēng)從沙漠外觀吹起大堆的沙。假設(shè)沙漠要支持生命，這種作用必不成少。科學(xué)家估計(jì)一年之中植物務(wù)必籠罩沙漠外觀的20%到40%。假設(shè)灌木間隔太遠(yuǎn)大于它們高度的5倍周邊的土壤就可能被吹走。假設(shè)沒有這些灌木作為養(yǎng)護(hù)，新的種子很難生長。另一方面，植物相互靠得太近卻會(huì)引起競爭地下水分。為制止競爭，一些灌木會(huì)釋放一種物質(zhì)來殺死那些距他們太近發(fā)芽的植物。除了一些種類的樹木和頑強(qiáng)的灌木外，大多數(shù)沙漠里還有青草、草本植物和其它年生植物。它們并不與長期生長的樹木競爭水份。當(dāng)雨后地表還潮濕時(shí)它們就急速發(fā)芽，然后在一個(gè)短時(shí)間里，給沙漠鋪上綠色地毯。這些小植物很快就消散了，幾