问题
多项选择题
经济寿命是指设备从投入使用开始，到因继续使用经济上不合理而被更新所经历的时间，取决于（）。
A．维护费用的提高
B．生产类型的变化
C．使用价值的降低
D．操作水平的提高
E．环境要求的提高
答案
参考答案：A, C
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经济寿命是指设备从投入使用开始，到因继续使用经济上不合理而被更新所经历的时间，取决于（）。
A．维护费用的提高
B．生产类型的变化
C．使用价值的降低
D．操作水平的提高
E．环境要求的提高
参考答案：A, C
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