Deep underground, in a circular tunnel 16 miles long, is a stream of trillions of tiny particles.

在很深的地下，一条循环的16英里长的地下隧道，有一条几万亿微小的粒子流。

youdao

Underground water resources, or oases, sufficient to support irrigated agriculture are found in dry stream beds and depressions.

在干河床和洼地处可找到充足的地下水资源或者绿洲来支持灌溉农业。

youdao

It must have been kept fresh by an underground stream, because the water was cold and clear.

NEWYORKER: Wakefield

Now, in this warren of rooms, except for the muffled sound of the crowd above, the only sound was the whooshing of an underground stream, redirected here from Roman times for irrigation and cleaning.

FORBES: Seeing The Colosseum As The Gladiators Did

They are widely regarded as a world-class natural attraction containing marvellous stream passages formed by three rivers that sink underground on the slopes of Cuilcagh Mountain.

UNESCO: Olympic torch carried through iconic Geopark