In 1863the first underground passenger railway in the world opened in London. It ran for just under seven kilometers and allowed people to avoid terrible __61__(crowd) on the roads above as they travelled to and ___62__ word. It took three years to complete and was built using an interesting method. This included digging up the road, ____63___(lay) the track and then building a strong roof over___64___ top. When all those had been done, the road surface was replaced.

Steam engines ___65__(use) to pull the carriages and it must have been___66__(fair)unpleasant for the passsengers, with all the smoke and noise. However, the railway quickly proved to be a great success and within six months, more than 25,000 people were using___67__ every day.

Later, engineers ____68___(manage) to construct railways in a system of deep tunnels (隧道）, which became known to the tube. This development was only possible with the ___69___ (introduce) of electric-powered engines and lifts. The central London Railway was one of the most ___70___(success) of these new lines, and was opened in 1900. It had white-painted tunnels and bright red carriages, and proved extremely popular with the public.