The plans for building the underground met with several problems and delays, but the fast track was finally opened in January 1863.A steam train pulled the cars along the fast underground track which was 6 kilometers(3.7 miles) long. About 30 000 people got on the subway the first day. Riders were treated to comfortable seats(standing up while the train was moving was not allowed),and pleasant decorations inside each of the cars. However, the smoke from the engine soon filled the air in the tunnels with ash and soot(煤灰),as well as chemical gases. Fans had to be put in the tunnels later to keep the air clean enough for people to breathe. Even with its problems, riding in the underground did catch on. It carried 9 million riders in its first year.

1. What led the British government to build the London underground?

A. Traffic jams and pollution.

B. Population and pollution.

C. Overcrowding and traffic jams.

D. The poverty and subway problems.

2. When the idea of the London underground was born, __________.

A. people began to build it immediately

B. the London underground wasn't built at once

C. no one agreed to the idea

D. the government didn't hope to build such an underground

3. The underlined phrase “catch on” most probably means “__________”.

A. be troublesome

B. become popular and fashionable

C. keep up with

D. seize

4. Which of the following is TRUE?

A. To make it possible for more workers to live in the city of London, the government built the subway.

B. There were so many problems and delays that in the 18th century the first subway opened.

C. The subway greatly eased the pressure of traffic.

D. There were not enough seats for the passengers the first day the subway opened.