数字证书的应用是为了解决信息传输中的什么问题（）

循环信用证按金额循环方式的不同，可以分为（）。

Inwhatseemsliketheprehistorictimesofcomputerhistory;theearth’spostwarera,therewasquiteawidespreadrumorthatcomputerswouldtakeovertheworldfrommanoneday.Alreadytoday,lessthanfiftyyearslater,ascomputersarerelievingusofmoreandmoreoftheroutinetasksinbusinessandinourpersonallives,wearefacedwithalessdramaticbutnotlessforeseenproblem.Peopletendtobeover-trustingofcomputersandarereluctanttochallengetheirauthority.Indeed,theybehaveasiftheywerehardlyawarethatwrongbuttonsmaybepushed,orthatacomputermaysimplymalfunction.Obviously,therewouldbenopointininvestinginacomputerifyouhadtocheckallitsanswers,butpeopleshouldalsorelyontheirowninternalcomputersandcheckthemachinewhentheyhavethefeelingthatsomethinghasgonewrong.Questioningandroutinedouble-checksmustcontinuetobeasmuchapartofgoodbusinessastheywereinpre-computerdays.Maybeeachcomputershouldcomewiththewarning:forallthehelpthiscomputermayprovide,itshouldnotbeseenasasubstituteforfundamentalthinkingandreasoningskills.

37.Accordingtothepassage,theauthorwouldprobablydisapproveof__________.

A.investmentincomputers

B.completedependenceoncomputers

C.double-checkoncomputers

D.theuseofcomputer

38.Intheauthor’sopinion,peopleshould__________.

A.bereasonablydoubtfulaboutcomputers

B.usecomputersforbusinesspurposesonly

C.substitutecomputersforbasicthinking

D.checkalltheiranswerswhenusingcomputers

39.Whatissuggestedinthispassage?

A.Computerwon’tchangeourpersonallives.

B.Computercancreateunforeseenproblems.

C.Computerhastakencontroloftheworld.

D.Computercannotaffectourbusinesses.

40.Whatisthemainpurposeofthispassage?

A.Tolookbacktotheearlydaysofcomputers.

B.Toexplainwhattechnicalproblemsmayoccurwithcomputers.

C.Todiscourageinvestmentincomputers.

D.Towarnagainstamentallylazyattitudetowardscomputers.

第二次世界大战后，国际市场上初级产品的价格贸易条件出现（）。

名词解释：电话银行