The Salk vaccine is a major factor in the fight to eradicate polio.
A、completelydestroyA
暂无解析
ThefirstimportantexpositionintheUnitedStateswasheldinPhiladelphiain1876.
Alligatorsstillexistinsomeofthedank潮湿swampsandbayous小海湾ofAlabama'scoastalregions.
Ella Grasso, elected governor of Connecticut in 1974, supported the enactment (given, granted) of a freedom-of-information law.
With lasers scientists can probe many physical processes, such as combustion, once beyond our ken.视野
The megaphone(microphone) makes the voice sound louder because it points sound waves in one direction and keeps them from spreading out in all directions.
