Formerly,intheUnitedStates,manynursesworkedasprivatedutynursesratherthaninhospitals.
TheSalkvaccineisamajorfactorinthefighttoeradicatepolio.
Batsfly,ratherthanglide,andthusaretheonlymammalscapableoftrueflight.
Oneofthegreatestbreakthroughsforprofessionalwomencamein1973whenthefieldofbankingopenedupforthem.
The fear of smallpox, which terrorized the eighteenth century, has no analogy(likeness) today.
Mary McCarthy s satires 讽刺文学 are couched in a prose style that has a classic precision.