The Salk vaccine is a major factor in the fight to eradicate polio.
A、completelydestroyA
暂无解析
Themegaphone(microphone)makesthevoicesoundlouderbecauseitpointssoundwavesinonedirectionandkeepsthemfromspreadingoutinalldirections.
Someseaurchins海胆havevenomous(toxin)spines
Anoversight遗漏(miss,overslaugh)inproofreadingoftenresultsinprintederrors.
Creamoftartar酒石,aweakacid,canbeaddedtoeggwhitestohelpthemfoam泡沫whentheyarebeaten
Formulatedin1823,theMonroeDoctrineassertedthattheAmericaswerenolongeropentoEuropeancolonization.
