The Salk vaccine is a major factor in the fight to eradicate polio.
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ThefirstimportantexpositionintheUnitedStateswasheldinPhiladelphiain1876.
Urbanrenewalprogramsstrivetoupgradeareasthatarebecomingslums.
Somecosmeticsmanufacturersattempttocapturetherose'sunmistakablefragrance香味insoapsandperfumes.
Thefearofsmallpox,whichterrorizedtheeighteenthcentury,hasnoanalogy(likeness)today.
Theflowerbudofawaterlily百合opensatsunsetsince.itsopeningistriggered(commence).bythedecreasedlight.