Passage4

Questions16to20arebasedonthefollowingpassage:

Successfulinnovationshavedrivenmanyoldertechnologiestoextinctionandhaveresultedinhigherproductivity,greaterconsumptionofenergy,increaseddemandofrawmaterials,acceleratedflowofmaterialsthroughtheeconomyandincreasedquantitiesofmetalsandothersubstancesinuseeachperson.Thehistoryofindustrialdevelopmentaboundswithexamples.

In1870,horsesandmulesweretheprimesourceofpoweronU.S.farms.Onehorseormulewasrequiredtosupportfourhumanbeingsaratiothatremainedalmostconstantformanydecades.Atthattime,hadanationalcommissionbeenaskedtoforecastthepopulationfor1970,itsanswerprobablywouldhavedependedonwhetheritsconsultantswereofaneconomicortechnologicalturnofmind.Hadtheybeen“economists”,theywouldprobablyhaveprojectedthe1970horsesormulepopulationtobemorethan50million.Hadtheybeen“technologists”,theywouldhaverecognizedthatthepowerofsteamhadalreadybeenharnessedtoindustryandtolearnandoceantransport.Theywouldhaverecognizedfurtherthatitwouldbetheprimesourceofpoweronthefarm.Itwouldhavebeendifficultforthemtoavoidtheconclusionthatthehorseandmulepopulationwoulddeclinerapidly.

16.Accordingtothepassage,whatsuppliedmostofthepoweronU.S.farmsin1870?

A.AnimalsB.HumansC.EnginesD.Water

17.WhichofthefollowingisNOTmentionedbytheauthorasaconsequenceofnewtechnologicaldevelopments?

A.Oldertechnologiesdieaway.

B.ThequalityoflifeisImproved.

C.Overallproductivityincrease.

D.Morerawmaterialsbecomenecessary.

18.Itcanbeinferredfromthepassagethatby1870.

A.technologybegantobemoreeconomical

B.thesteamenginehadbeeninvented

C.theU.S.horsepopulationwasabout10million

D.anationalcommissionwasabout10million

19.Inthesecondparagraph,theauthorsuggeststhat“economists”would.

A.plantheeconomythroughyearlyforecasts

B.failtoconsidertheinfluenceoftechnologicalinnovation

C.valuetheeconomiccontributionoffarmanimals

D.consultthenationalcommissionontheeconomy

20.Whatistheauthor’sattitudetowardchangesbroughtonbytechnologicalinnovations?

A.Heisexcitedaboutthem.

B.Heacceptthemasnatural.

C.Heisdisturbedbythem.

D.Hequestionstheirusefulness.

关于问诊技巧的描述不正确的是

正常枕先露分娩时，仰伸发生于

当正压人工呼吸与胸外按压配合进行时大约每分钟各多少次?

早接触，早吸吮要求在出生后