The quantitative prediction and comprehensive appraisement of maneuverability of self-propelled gun have provided theoretic foundation for maintenance guarantee of weapon equipments.

定量预测和综合评价自行火炮的机动能力，为武器装备的维修保障提供了理论依据和手段。

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Although Luxor is a popular tourist destination and sees thousands of foreign visitors every year, there is no guarantee balloon pilots and other maintenance staff can speak English.

BBC: Luxor balloon survivor Linda Lea remembers ordeal