In theory, the Army could use such a system to approach targets covertly and drill through concrete, steel, wood, or other materials from a stand-off distance equal to the length of a football field.

理论上，美国陆军将利用该系统实现某些目标，既通过远距离(超过一个足球场的距离)的设备对混凝土、钢铁、木头以及其他材料进行隐蔽的击穿作业。

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Men approach with their hands behind their backs while the women use their skirts to keep the men enticed from a respectful distance.

男人们手背在身后往前凑，女人们则利用裙子把男人们挡在礼貌的距离外。

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All are admonished by guides to keep a healthy distance from curious bears that approach their buggies.

所有的手册都告诫说与那些接近卡车的好奇的北极熊保持安全的距离。

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This approach also favors secret construction but at a greater distance from Israeli air bases and with more room for improvisation.

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The tour guide will instruct you to maintain a safe distance from the birds, but be prepared for them to approach you as penguins can be extremely curious.

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It will make its closest approach to the Sun - at a distance of not much more than a million km from the Sun's surface - on 28 November.

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