Themegaphone(microphone)makesthevoicesoundlouderbecauseitpointssoundwavesinonedirectionandkeepsthemfromspreadingoutinalldirections.
A、slitheringThe Native American interpreter Sacajawea was a valuable member of the Lewis and dark expedition in 1805.
The controls of most modern airplanes can be operated either manually or automatically.
Some cosmetics manufacturers attempt to capture the rose's unmistakable fragrance香味 in soaps and perfumes.
Eyespots, the most rudimentary eyes, are found in protozoan原生動(dòng)物 flagellates 鞭毛蟲(chóng) , flatworms 扁形蟲(chóng) , and segmented worms片段 蠕蟲(chóng) .
TheNativeAmericaninterpreterSacajaweawasavaluablememberoftheLewisanddarkexpeditionin1805.
