1. Until the mid-19th century, no one had ever tried to build a railway through the Alps because railway engineering was still very new and the Alps were a challenging environment.
2. Ghega used brick and stone instead of iron and steel to build most of the important structures for the railway and used waste materials for many buildings.
3. The construction of the Semmering Railway was a difficult but successful project that realized Ghegaʼs vision of architecture in harmony with the natural environment.
4. The Semmering Railway had to be constructed by hand because explosives and advanced tunnel-digging equipment did not yet exist.

Fill in the blanks, thinking back to the answer to the question following each section numbers. Read the finished summary aloud.

The Semmering Railway is the world’s ①（first mountain railway）, which was designed by Karl Ritter von Ghega in the 19th century. At that time people believed it would be impossible to build a railway through the Alps ②（with the technology of the time）, and it took some time for Ghega’s plan to be accepted because there were ③（no previous examples） similar to the project. The construction work finally began in 1848, and over six years about 20,000 people worked on it until it was completed. During this period, many workers were killed in accidents or died of disease. In spite of such difficulties, Ghega realized his idea of building the railway in ④（harmony with the natural environment）. Thanks to his vision, the Semmering Railway still plays a role not only as ⑤（an important transportation route）, but also ⑥（a wonderful sightseeing destination）.