The system model consists of three levels, including initial planning, decision making and detail planning.

系统模型由三个层次组成，即初步规划层，决策层和详细规划层。

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Initial planning is the most vital part of a project.

初步策划是项目最重要的一部分。

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Initial planning is the most vital part of a project.

初步策划是项目最重要的一部分。

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