The high point in railroad building came with the construction of the first transcontinental system. In 1862 Congress authorized two western railroad companies to build lines from Nebraska westward and from California eastward to a meeting point，so as to complete a transcontinental crossing linking the Atlantic seaboard with the Pacific. The Government helped the railroads generously with money and land. Actual work on this project began four years later. The Central Pacific Company, starting from California, used Chinese labor, while the Union Pacific employed crews of Irish labourers. The two groups worked at remarkable speed, each trying to cover a greater distance than the other. In 1869 they met at a place called Promontory in what is now the state of Utah. Many visitors came there for the great occasion. There were joyous celebrations all over the country, with parades and the ringing of church bells to honor the great achievement.
The construction of the transcontinental railroad took_.
A. 9 years B. 7 years C. 4 years D. 3 years
講解答案：
D 這是一道有關年代考點的細節(jié)題。根據(jù)文章：美國國會1862年授權兩家鐵路公司建設橫貫美國東西兩岸的鐵路，實際修建時間為1866年(國會授權后4年開始修建)，于1869年在猶他州的Promontory相會。因此是3years,那么D為正確答案。一些考生由于不細心，未看淸實際施工的時間應為1866年,而將其誤為1862年，所以錯選了B。
