TheSalkvaccineisamajorfactorinthefighttoeradicatepolio.
A、completelydestroyDoubleEagleinthefirsttransatlanticballoon,wasgreetedbyavidcrowdsinFrance.
Urbanrenewalprogramsstrivetoupgradeareasthatarebecomingslums.
Alligatorsstillexistinsomeofthedank潮湿swampsandbayous小海湾ofAlabama'scoastalregions.
Thefirstpaperwasmadefromthebarkofthemulberrytree.
WhileBillieHolidaydidnotinventthemusiccalled"theblues",shemostassuredlyhelpedpopularizeit.
