London Underground The world’s first subway was built in London in 1863. At the time, the gover..

40-43  CBBC 40. 选C。根据文章第一段源旁中乱塌“the government was looking for a way to reduce traffic problems in the city of London.”可知，C项是正确的。41. 选B。根据文章第二段“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.”，可知应该选B。42. 选B。雹陪橡根据文章最后一句“It carried 9 million riders in its first year.”，可知，catch on的意思为“受欢迎的”。43. 选C。当初建造地铁的目的就是为了缓解交通，最后为缓解了英国的交通问题。