1·I always travel by underground.
我总是乘地铁。
—— 《牛津词典》
2·It is very convenient to travel in London by underground.
在伦敦游玩时，坐地铁是很方便的。
3·This is one of my favourite exercises as you can do it almost anywhere, I say almost as I couldn't imagine doing it on the underground without getting strange looks from those around me.
这是我最喜欢的眼操之一，因为几乎随时随地都能做，我说几乎的意思就是，我无法想象在地铁上做这项眼操时周围会没有奇怪的表情看着我。
4·Although cities are stretching their underground transportation networks like spiderwebs, new lines are too costly to reach every corner of the city.
尽管各个城市都在像蜘蛛网一样扩张地铁交通网络，要想新线路抵达城市的每个角落成本非常昂贵。
5·Mr Doukaiev had lodged in a hotel just yards from Denmark's busiest underground station, leading to speculation he may have had similar designs.
都凯夫曾在距离丹麦最繁忙的地铁车站仅数码的酒店住宿，不得不让人猜测他可能有类似的计划。