underground subterranean secret on the ground secret (activity)
The dug-outs were secure from everything but a direct hit.
除非是直接被击中,否则这个地下掩体是非常安全的。
—— 柯林斯例句They are accused of organising and financing an underground youth movement.
他们被指控组织并资助地下青年运动。
—— 柯林斯例句I struggled into a bathrobe and staggered down the stairs.
我挣扎着穿上浴衣,踉跄地下了楼。
—— 柯林斯例句People were making for the air-raid shelters below ground.
人们正奔向地下防空洞。
—— 柯林斯例句The groundwater is only feet beneath the city streets.
地下河距离上面的城市街道只有几英尺。
—— 柯林斯例句