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.