劣質(zhì)燃油在霧化加熱器中的預(yù)熱溫度高低主要決定于:
A、加熱器熱容量B
暫無解析
Intheearlieststagesofman'sdevelopmenthehadnomoreneedofmoneythananimalshave.Hewascontentwithverysimpleformsofshelter,madehisownroughtoolsandweaponsandcouldprovidefoodandclothingforhimselfandhisfamilyfromnaturalmaterialsaroundhim.Ashebecamemorecivilized,however,hebegantowantbettershelter,moreefficienttoolsandweapons,andmorecomfortableandmorelastingclothingthancouldbeprovidedbyhisownneighborhoodorbytheworkofhisownunskilledhands.Forthesethingshehadtoturntotheskilledpeoplesuchassmiths,leatherworkersorcarpenters.Itwasthenthatthequestionofpaymentarose.
Atfirsthegotwhathewantedbyasimpleprocessofexchange.Thesmithwhohadnotthetimetolookafterlandorcattlewasgladtotakemeatorgrainfromthefarmerinexchangeforanaxeoraplough.Butasmoreandmoregoodswhichhadnofixedexchangevaluecameonthemarket,exchangebecametoocomplicatedtobesatisfactory.Anotherproblemarosewhenthosewhomadethingswantedtogetstocksofwoodorleather,oriron,buthadnothingtoofferinexchangeuntiltheirfinishedgoodswereready.Thusthedifficultiesofexchangeledbydegreestotheinventionofmoney.Insomecountrieseasilyhandledthingslikeseedsorshellsweregivenacertainvalueandthefarmer,insteadofpayingthesmithforanewaxebygivinghimsomemeatorgrain,gavehimsomanyshells.Ifthesmithhadanyshellsleftwhenhehadboughthisfood,hecouldgetstocksoftherawmaterialsofhistrade.Insomecountriesquitelargethingssuchascowsorcamelsorevenbigflatstoneswereusedfortrade.Later,piecesofmetal,bearingvaluesaccordingtotherarityofthemetalandthesizeofthepieces,orcoinswereused.Moneyasweknowithadarrived.
1.Exchangeofgoodsbecamedifficultbecause_________.
Amanbecamemorecivilized
Bsmithsbegantolookafterlandorcattleintheirsparetime
Cmoreandmoregoodswhichhadnofixedexchangealuescametothemarker
Dfarmershadn'tenoughgrainormeattoprovidefor
skilledworkers
2.Moneywasnotuseduntil_______.
Apaperwasinvented
Bpeoplepracticedasimpleprocessofexchange
CnothingcouldbeofferedinexchangeDtheexchangeofonethingforanotherbecametoocomplicated
3.Thebesttitleforthispassageis_____.
AWhatismoney
BWhataremoney'sfunctions.
CTheimportanceofmoney
DThebeginningofmoney
孩子普遍容易受到電視電影中不良內(nèi)容的影響。
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男女同校會大大分散學(xué)生學(xué)習(xí)的注意力。
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