【判断题】【消耗次数：1】
周期性的交变切削力是导致自激振动的原动力，该说法（ ）
①
正确
②
错误
参考答案：
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相关题目
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卵巢在青春期之前无周期性变化
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每个周期中往往只形成一个成熟卵泡
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关于子宫颈黏液的周期性变化，下列说法错误的是（ ）
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在雌激素的作用下量多，质地稀薄
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卵泡期，干燥后镜检可呈现椭圆体
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