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Unit 8 Transportation
Expansion 8
3 In many large cities
there is a subway system of underground trains.
Cities have different names for their subways.
The London Underground is called The Tube.
In San Francisco,it is called BART
(Bay Area Rapid Transit).
Some subway systems,like Chicago's,
for example,are quite old.
It opened in 1897.
Others are more recent.
For example,Mexico City's subway
started in 1969.
In a subway,the train lines
form a separate transportation system.
They usually go through underground tunnels
in the center of the city and above the ground
on the edge.
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