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