求翻译：二级维护作业的中心内容包括部分总成解体、全面调整检查、消除存在的故障和隐患，目的是保持和恢复汽车的技术状况，提高教练车的动力性和经济性，减少教练车的尾气排放和噪声污染，保证教练车行驶的可靠性和安全性。是什么意思？

Two maintenance centers including the disintegration of some assembly, overall adjustment check, the existence of faults and eliminate hidden dangers, the purpose is to maintain and restore the vehicle's technical condition, the coach cars to improve power and economy, reduce vehicle emissions coach

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Two level of maintenance work central content including the partial unit disintegration, the comprehensive adjustment inspection, the elimination existence breakdown and the hidden danger, the goal is maintains and restores the automobile the technical condition, enhances the driver training car the

Secondary maintenance job Center covers part of the dissolution of the Assembly, a comprehensive checking, eliminating for failures and breaches, aims to maintain and restore the car's technical condition, improve coaching vehicle power performance and fuel economy, reduced coach traffic exhaust emi