传统的固定电话网是由()三部分组成。
B
暂无解析
Marytiptoedoverandtooktheclockawaybecauseshehatedtohearit()whenshewastryingtogotosleep.
There_____nothingmorefordiscussion,themeetingcametoanendhalfanearlier.
At______,photographyisachemicalprocess,duringwhichalight-sensitivematerialisalteredwhenexposedtolight.
ThediscoveryoftheAntarcticnotonlyprovedoneofthemostinterestingofallgeographicaladventures,butcreatedwhatmightbecalled“theheroicageofAntarcticexploration”.Bytheirtremendousheroism,mensuchasShakleton,Scott,andAmundsencausedanewcontinenttoemergefromtheshadows,andyetthatheroicage,littlemorethanacenturyold,isalreadypassing.Modernscienceandinventionsarerevolutionizingtheendurance,futurejourneysintotheseicywasteswillprobablydependonmotorvehiclesequippedwithcaterpillartractionratherthanonthedogsthatearlierdiscoverersfoundsoinvaluableandhardlycomparable.
FewrealizethatthisAntarcticcontinentisalmostequalinsizetoSouthAmerica,andenormousfieldofworkawaitsgeographersandprospectors.Thecoastsofthiscontinentremaintobeaccuratelycharted,andthemapingofthewholeoftheinteriorpresentsaformidabletasktothecartographerswhoundertakethework.Oncetheirlaborsarecompleted,itwillbepossibletoprospectthevastnaturalresourceswhichscientistsbelievewillfurnishoneofthelargesttreasurehoardsofmetalsandmineralstheworldhasyetknown,andalmostinexhaustiblesourcesofcopper,coal,uranium,andmanyotheroreswillbecomeavailabletoman.SuchdiscoverieswillusherinaneraofpracticalexploitationoftheAntarcticwastes.
Thepolardarknesswhichhidesthiscontinentforthesixwintermonthswillbedefeatedbyhugebatteriesoflight,andmakepossibletheestablishingofair-fieldsforthefutureinter-continentalairservicesbymakingtheseareasaslightasday.Presentflyingrouteswillbecompletelychanged,fortheAntarcticrefuelingbaseswillmakeflightsfromAustraliatoSouthAmericacomparativelyeasyoverthe5,000milesjourney.
Theclimateisnotlikelytoofferaninsuperableproblem,fortheexplorerAdmiralByrdhasshownthattheclimateispossibleevenformencompletelyuntrainedforexpeditionsintothosefrozenwastes.Someofhispartiesweremenwhohadneverseensnowbefore,andyetherecordsthattheysurvivedtherigorsoftheAntarcticclimatecomfortably,sothat,providedthattheappropriateinstallationsaremade,wemayassumethathumanbeingsfromallcountriescouldlivetheresafely.Byrdevenaffirmsthatitisprobablythemosthealthyclimateintheworld,fortheintensecoldofthousandsofyearshassterilizethiscontinent,andrendereditabsolutelygermfree,withtheconsequencesthatordinaryandextraordinarysicknessanddiseasesfromwhichmansuffersinotherzoneswithdifferentclimatesarehereutterlyunknown.Thereexistnoproblemsofconservationandpreservationoffoodsupplies,forthelatterkeepindefinitelywithoutanysignsofdeterioration;itmayevenbethatlatergenerationswillcometoregardtheAntarcticasthenaturalstorehouseforthewholeworld.
Plansarealreadyonfoottosetuppermanentbasesontheshoresofthiscontinent,andwhatsofewyearsagowasregardedasa“deadcontinent”nowpromisestobeamostactivecenterofhumanlifeandendeavor.
1.WhendidmanbegintoexploretheAntarctic?
A.About100yearsago.
B.Inthiscentury.
C.Atthebeginningofthe19thcentury.
D.In1798.
2.Whatmusttheexplorersbe,eventhoughtheyhavemodernequipmentandtechniques?
A.Braveandtough
B.Stubbornandarrogant.
C.Well-likedandhumorous.
D.Stoutandsmart.
3.Themosthealthyclimateintheworldis___.
A.inSouthAmerica.
B.intheArcticRegion.
C.intheAntarcticContinent.
D.intheAtlanticOcean.
4.WhatkindofmetalsandmineralscanwefindintheAntarctic?
A.Magnetite,coalandores.
B.Copper,coalanduranium.
C.Silver,naturalgasanduranium.
D.Aluminum,copperandnaturalgas.
5.Whatisplannedforthecontinent?
A.Buildingdamsalongthecoasts.
B.Settingupseveralsummerresortsalongthecoasts.
C.Mappingthecoastandwholeterritory.
D.Settinguppermanentbasesonthecoasts.