The shop glass content including ballast source selection principle and ballast means of transportation.
铺碴的内容包括道碴来源地的选取原则和道碴的运输方法.
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The selection principle is selecting stand from fine seed source and from them selecting fine individuality.
论述了优树选择应遵循优良种源区选择优良林分,优良林分中选择优良单株的系统选择原则.
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