The central body of the plane is made entirely of carbon composite material, which makes the plane lighter and more fuel efficient.

机身主体全部由碳合成材料制成，因此重量更轻，更加省油。

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It also increases the use of costly carbon-fiber body panels (the hood and roof) and other composite materials, to save weight.

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To convince wary airline executives that carbon-fiber body material was strong, Boeing sales teams carried samples and hammers, letting airline executives whack the composite with all their might.

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