The rest of the concept relied on gravity, which guaranteed that the surface of the molten metal was perfectly flat and horizontal.

其余的概念依赖于重力，它保证了熔融金属的表面是完全平坦和水平。

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The metal had been beaten flat.

那块金属被锤薄了。

《牛津词典》

Almost all cargo vessels, by contrast, have flat bottoms, which allow a larger volume to be kept buoyant for a given amount of hull metal.

相比之下，几乎所有商船的底部都是平的，因为这样可以为庞大的金属船壳提供更大的浮力。

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In his 50-year career, Ovshinsky received more than 400 patents in the U.S. and more than 800 foreign patents covering a range of technologies, including nickel-metal hydride batteries, rewritable CDs, DVD optical discs, flat-screen liquid crystal displays, hydrogen fuel cells, thin-film solar cells and others.

FORBES: Stanford Ovshinsky, Battery Genius Behind Smartphones And Hybrids, Dies At 89

Same all-metal chassis but also, the same flat keyboard.

ENGADGET

From its heyday in the 1970s, table hockey featuring stick figures on a flat board controlled by metal rods, wielding mini-sticks swatting at a small puck was nearly wiped out by videogames and the Internet.

WSJ: Table Hockey, on Ice Since Heyday in 1970s, Makes a Comeback