試題詳解

49 Which of the following is one of the challenges engineers and workers had to face during the construction of the Qinghai-Tibet Railroad?
(A) Travelers from Beijing may suffer altitude sickness in Lhasa.
(B) The idea of a train trip is not as appealing as that of air travel.
(C) The tourism industry is impossible on the snow-covered permafrost.
(D) The railroad track may become bent or curved if frozen ground melts.