RecentlytheWorldHealthOrganizationannouncedthatthediseaseofsmallpox（天花）hadalmostbeenwipedoutinmostpartsoftheworldthankstowidespreadvaccination（种牛痘）.Mostpeoplearevaccinatedatleastonceintheirlivesandiftheywishtotravelfromonecountrytoanothertheymustbeabletoprovethattheyhavehadarecentvaccination.Inthiswaythediseasehasbeenpreventedfromspreadingandtodayoneseldomhearsofitatall.
ThisismainlybecauseofthegreatdiscoverymadebyavillagedoctorEdwardJennerinabout1798whenhepublishedhisreportofhisnewexperimentcalledvaccination(fromtheword‘vacca’meaningacow).Jennerdiscoveredthatpeoplewhoworkedwithcattleoftensufferedfromaharmlessdiseasewhichtheycaughtfromthecattlebutthesepeopleneverseemedtogetsmallpox.Soheexperimentedbyputtingthediseaseintoasmallopeningonthearmsofhealthypeopleandthoughtheirarmsbecamepainfulforadayortwotheysoonrecoveredandnoneofthesepeopleevergotsmallpox.
Sothenewsofthewonderfuldiscoveryspreadtoothercountriesandpeople
rushedtotheirdoctorstobevaccinated.Inmanycountriesthesimplewaytodealwiththearmwasdoneonthousandsofpeopleandtheterriblesmallpoxbegantodisappear.
71．Vaccinationagainstsmallpoxhasbeensosuccessfulthat_________.
A．thediscoverermadealargeamountofmoney
B．DrJennerwasgivenaprizebytheWorldHealthOrganization
C．smallpoxhasalmostdisappearedinmostcountries
D．smallpoxwasnolongerinexistenceonearth
72．SmallpoxhasbeenpreventedfromspreadingthroughthefollowingmeasuresEXCEPTthat_____.
A．mostpeoplewerevaccinatedagainstthediseaseatleastonce
B．peoplegoingabroadshouldpromisenottospreadthedisease
C．peopletravellingfromonecountrytoanothermustprovethey
arevaccinated
D．peoplemustbevaccinatedshortlybeforegoingtoforeigncountries
73．WhatledDrJennertoexperimentwithvaccinationwasthat________.
A．hewantedtomakeagreatdiscoveryandpublishit
B．vaccinationcouldmakepeople'sarmssafe
C．hetriedtocurethefarmersofsomediseasecaughtfromthe