我上次想了一下，没有电脑的时候这些都怎么算的呢，估计安全系数要选的很大，全用手算工作量巨大

来源: 早晨从中午开始于 2020-07-07 17:27:30 [旧帖] [给我悄悄话] 本文已被阅读：次

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