Passage4

Questions16to20arebasedonthefollowingpassage:

Thenewglobalsatellitecommunicationssystemswillofferthreekindsservice,whichmayoverlapinmanydifferentkindsofreceivers.

VOICE.SatellitetelephoneswillbeabletomakecallsfromanywhereontheEarthtoanywhereelse.Thatcouldmakethemespeciallyusefultoremote,thirdworldvillages(someofwhichalreadyusestationarysatellitetelephones),explorersanddisaster-reliefteams.Today’smobiletelephonesdependonearth-boundtransmitters,wheretechnicalstandardsvaryfromcountrytocountry.Sobusinesstravelerscannotusetheirmobilephonesoninternationaltrips.Satellitetelephoneswouldmakethatpossible.

MESSAGING.Satellitemassagershavethesameglobalcoverageassatellitetelephones,butcarrytextalone,whichcouldbeusefulforthosewithlaptopcomputers.Equippedwithasmallscreenliketoday’spapers,satellitemassagerswillalsoreceiveshortmessages.

TRACKING.Voiceandmessagingsystemswillalsotelltheiruserswheretheyaretowithinafewhundredmeters.Combinedwiththemessagingservice,thelocationservicecouldhelprescueteamstofindstrandedadventurers,thepolicetofindstolencars,exporterstofollowtheprogressofcargoes,andhaulagecompaniestocheckthatdriversarenotdetouringthepub.America’smilitaryGlobalPositioningSystem(GPS)satellitewillprovidebetterpositioninginformationtoanyonewhohasareceiverfortheirsignals,butGPSdoesnotcarrymessages,sosuchareceivercannotbeusedonitsownfortrackingorrescue.Bythemid-1990s,GPSreceiverswillbeabletotellpeoplewheretheyaretowithin70metersanywhereintheworld,andtowithinameterorsoinareaswheretheserviceissupplementedbyground-basedtransmitter.

16.Globalsatellitecommunicationssystemswillbeusefulto.

A.laptopcomputerusers

B.remotevillages

C.disaster-reliefteams

D.allabove

17.Satellitetelephonewillmake.

A.businesstravelersusemobilephonesoninternationaltrips

B.possiblecallsfromanywhereonearthtoanywhereelse

C.explorershappy

D.allabove

18.Whichofthefollowingistrue?

A.ThepositioningprecisionofthevoicesystemisbetterthanthatofGPS.

B.ThepositioningprecisionofGPSisBetterthanthatofthevoicesystem.

C.ThepositioningprecisionofthemessagingsystemisbetterthanofGPS.

D.Thepositioningprecisionofvoicesystemisbetterthanthatofthemessagingsystem.

19.Whatcanwesayaboutthenewglobalsatellitecommunicationssystems?

A.Theyarewidelyused.

B.Theyareveryhelpful.

C.Theyarecostly.

D.BothAandB.

20.Whichofthefollowingmaybethebesttitleforthepassage?

A.GlobalSatelliteCommunications

B.NewVoiceandMessagingSystem

C.NewGenerationSatellite

D.AlwaysinTouch

ABC复苏方案指什么?

第二产程初产妇超过()小时，经产妇超过()小时尚未分娩为第二产程延长。

活跃期停滞为活跃期宫口扩张停止大于()小时。

Thatradiocompanyissobigthatithasalotof____inforeigncountries.