The underground system is also known as the Tube, due to the characteristic shape of the subway tunnels.

地铁系统因其地铁隧道的典型形状也被称为地下管道。

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An estimated half a million mice live in the Underground system so that should keep them both busy for a while.

地铁中居住着约50万只老鼠，这够姊妹两忙上一阵子的了。

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In order to identify out the existence of the system and its structure, the geophysical electromagnetic technique is applied to detect and position the underground system.

为了查清该地下灌排系统的存在及其构造，采用地球物理电磁法进行了探测。

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London may be famous for its red double-decker buses, but it is the underground system, parts of it more than a hundred years old, that is especially vulnerable.

VOA: standard.2010.04.01

"These difficult to reach populations frequently go underground and remain not visible to the medical delivery system,"

VOA: standard.2009.11.15

looked at things like where should they locate waste water treatment facilities because of the impacts of climate change, what risks are likely to occur to their subway system because it's underground and already requires enormous pumping of water during certain large rainfall events."

VOA: standard.2010.06.14

London Stansted airport is a 45-minute journey from the capital and getting to London Heathrow by the underground system can take 50 minutes from parts of the city.

BBC: HS2 'will bring Birmingham Airport closer to London'

The London Underground, known as the Tube, opened in 1863, making it the oldest underground system in the world, and this year, a series of celebrations are planned for its 150th anniversary.

BBC: Living in: Great cities for public transport

The sleek underground system, which looks like it was transplanted from Japan, is in jarring contrast to the normal chaos of India.

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