It is well-known that it will take travelers only 48 hours by train to go from Beijing to Lhasa， the capital of west China's Tibet on July 1 this year. Travelers can enjoy the beautiful views during the 48 hour train ride.

    The new railway line will be controlled by the Beijing' s West Railway Station from July 1， 2006. The most important part of the line， the Qinghai-Tibet Railway， has been completed.

    The Qinghai-Tibet part of the railway is the world's highest railway. About 960 kilometers of the train tracks are 4，000 meters above sea level. The highest parts reach 5，072 meters.

    The railway is the world' s longest plateau railroad which is 1，956 kilometers long， from Qinghai's capital Xining to Lhasa in Tibet. The Golmud-Lhasa part is 1，142 kilometers long and goes across the Kunlun and Tanggula mountain ranges.

    The trains running on the Qinghai-Tibet Railway have very good conditions. If the passengers feel hard to breathe， they will be provided with oxygen masks， because all of the trains have oxygen supplying equipments.

阅读下面的古诗，完成各题

自湘东驿^①遵陆^②至芦溪^③

清查慎行

黄花古渡接芦溪，行过萍乡路渐低。

吠犬鸣鸡村远近，乳鹅新鸭岸东西。

丝缫^④细雨沾衣润，刀剪良苗出水齐。

犹与湖南风土近，春深无处不耕犁。

      【注释】①驿：驿站，中国古代供传递官府文书和军事情报的人或来往官员途中食宿、换马的场所。②遵陆：沿着陆路；走陆路。③芦溪：地名，在今江西省萍乡市。下文的“黄花古渡”“萍乡”也是地名。④丝缫：指春雨像蚕丝一样丝丝缕缕、绵绵不断。

词义的演变包括____、____、____和____等现象。