TheSalkvaccineisamajorfactorinthefighttoeradicatepolio.
A、completelydestroySomeseaurchins海胆havevenomous(toxin)spines
The fear of smallpox, which terrorized the eighteenth century, has no analogy(likeness) today.
An oversight 遗漏 (miss, overslaugh) in proofreading often results in printed errors.
Themegaphone(microphone)makesthevoicesoundlouderbecauseitpointssoundwavesinonedirectionandkeepsthemfromspreadingoutinalldirections.
With the acquisition of smaller companies by larger ones, the 1960's saw a wave of new conglomerates.
