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【单选题】
This is a student essay about the growth in air travel. Read the first paragraph below, and choose which sentence is most suitable as a paragraph leader. ........................... IATA, the trade association for the world’s airlines, estimates that revenues from air travel rose from $465 billion in 2006 to $705 billion in 2016. In addition the total number of passengers rose from 2.2 billion to 3.8 billion during the same period (IATA 2017). There are a number of different reasons for this rise, including low air fares and economic development, particularly in Asia, but there are several factors that may lead to a slowdown in this growth in air travel.A.
In the last decade, air travel has become much more popular than other forms of transport.
B.
At the global level, the average cost of air travel had fallen significantly.
C.
At the global level, air travel has increased dramatically in the last 10 years.
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