The first important exposition in the United States was held in Philadelphia in 1876.
A、exhibitionA
暂无解析
WhileBillieHolidaydidnotinventthemusiccalled"theblues",shemostassuredlyhelpedpopularizeit.
Thecontrolsofmostmodernairplanescanbeoperatedeithermanuallyorautomatically.
TheSalkvaccineisamajorfactorinthefighttoeradicatepolio.
Eyespots,themostrudimentaryeyes,arefoundinprotozoan原生动物flagellates鞭毛虫,flatworms扁形虫,andsegmentedworms片段蠕虫.
Thewheelsofthefirstroadvehicleswerefashionedfromcrudestonedisks.
