B Tower Bridge is a bascule bridge ( 吊桥 ) in London , over the River Thames.It is close to the Tower of London , which gives it its name.It's sometimes mistaken as London Bridge , which is the next bridge upstream. In the second half of the nineth century , increased business development in the East End of London caused a requirement for a new river crossing downstream of London Bridge.A Special Bridge or Subway Committee was formed in 1876 to find a way to settle the river crossing problem.It opened the design of the crossing to public competition.Over 50 designs were received.The consideration of the designs lasted several years , and it wasn't until 1884 that a design sent by Horace Jones was sanctioned . Building of the bridge started in 1886 and took 8 years' hard work of 432 building workers.Over 70,000 tons of concrete ( 混凝土 ) were sunk into the river bed to support the bridge.Over 11,000 tons of steel provided the framework ( 框架 ) for the towers and walkways.This was then coated in Cornish granite and Portland Stone , both to protect the steelwork and to give the bridge a pleasing appearance.Jones died in 1887 , and another engineer took over his work.The bridge was opened in 1894. The bridge sits almost directly above the Tower Subway , the world's first underground tube railway , which , until the bridge was opened , was the shortest way to cross the River Thames.A computer system was installed ( 安装 ) in 2000 to control the raising and lowering of the bascules.However , this has proved less reliable than expected , resulting in the bridge being stuck in the open or closed positions for a number of times. 24 . What does Paragraph 1 say about Tower Bridge? A . It's named after a famous person. B . It's another name for London Bridge. C . It's not far from the Tower of London. D . It's the only bridge over the River Thames. 25 . Which of the following can best replace the underlined word “sanctioned” in Paragraph 2? A . Tried. B . Received. C . Discovered. D . Passed. 26 . What does Paragraph 3 mainly talk about? A . The history of Tower Bridge. B . The building of Tower Bridge. C . The influence of Tower Bridge. D . The importance of Tower Bridge. 27 . What can be known from the last paragraph? A . Many breakdowns have happened to Tower Bridge. B . The computer system works better than expected. C . The underground tube railway has a history of less than 20 years. D . The Tower Subway is the shortest way to cross the River Thames.