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。

youdao

We can't instantiate instances of abstract classes, even when all their field and method members are concrete.

我们不能实例化一个抽象类，即使它们的字段和方法都是具体的。

youdao

Status: Field-testing for self-sensing concrete in progress.

现状：自行感知的混凝土现场测试正在进行中。

youdao

"It's extraordinary that the Lib Dems are still claiming that they will protect green spaces when they plan to concrete over our countryside with thousands more houses on green field sites, " she said.

BBC: Nick Clegg

Tomorrow, my fellow ministers and I will meet with business leaders from the United States and other APEC economies to work on concrete, practical measures that will help to level the playing field across the region.

WHITEHOUSE: Our Top Stories

It comprised a wide range of educational activities including field trips to enable students to explore various World Heritage sites and to take stock of concrete sustainable development issues.

UNESCO: Education