The output curve of a product is generally S-shape curve during its economic life period.
个别产品的产值(产量)曲线在其经济寿命周期里一般是一条S形曲线。
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She said the tree – which re-rooted itself in 1820 after being blown down in a storm and grew back in an 'inverted S-shape' – was already difficult to get close to because of its shape.