a field army

A field army was composed of armies, an army of corps (originally called columns), a corps of divisions, and a division of regiments.

野战军以下辖兵团，兵团辖军(即原来的纵队)，军辖师，师辖团。

One of the characteristics of mobile warfare is fluidity, which not only permits but requires a field army to advance and to withdraw in great strides.

运动战的特点之一，是其流动性，不但许可而且要求野战军的大踏步的前进和后退。

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。