At the beginning of the 20th century, the railroads were used to transport everything. Powerful railroad
companies made fortunes without having to be accountable to the public or considerate of customers. [ 19 ] But ears and trucks changed all of that. And by 1970, the rail industry was beset with problems. Trucks were taking all the new business. And even so, the rail industry remained indifferent to customers. Also, many regulations kept the rail industry from adjusting to shifting markets. But in 1980, the rail industry entered the modem era when a deregulation bill was passed that allowed railroad companies to make quick adjustments to fees and practices. Companies reduced their lines by 1/3 and used fewer employees. They also took steps to minimize damage to products and to increase their shipping capacity by stacking freight containers on railroad cars. [ 20 ] To accommodate these taller loads, under passes and tunnels were enlarged. The image of the rail industry has changed dramatically. Today companies are very responsive to customers and are gaining increasing market share in the shipping industry. The railroad safety record is also strong. Freight trains  have an accident rate that is only1/3 of that of the truck industry. [ 21] Trains also come out ahead of the trucks on environmental grounds because they give off only 1/10 to 1/3 the pollution that is emitted by trucks. And railroading does not wear out highways as trucks do.
What development caused the decline in the use of railroads?
【解题思路】
1．四项均为名词短语。
2．三项含有与交通运输有关的词汇(freight containers，railroad tracks，automotive industry)。
3．三项明显为不利因素(over sized，safety problems，high cost)。
结论：本题有可能考查导致某结果的不利因素。
【解析】题干问是什么的发展导致铁路运输的应用率下降。20世纪初，铁路运输业曾盛极一时．一切运输都依赖铁路。后由于汽车运输业的发展，铁路运输一度衰退，到了20世纪70年代，卡车运输包揽了很多新业务。可见铁路运输是受到了汽车运输业发展的影响。故选C。