Assuming that a constant travel-time budget, geographic constraints and short-term infrastructure constraints persist as fundamental features of global mobility, what long term results can one expect In high-income regions, (41) North America, our picture suggests that the share of traffic (42) supplied by buses and automobiles will decline as high-speed transport rises sharply. In developing countries, we (43) the strongest in crease to be in the shares first for buses and later for automobiles. Globally, these (44) in bus and automobile transport are partially offsetting. In all regions, the share of low speed mil transport will probably continue its strongly (45) decline.
We expect that throughout the period 1990--2050, the (46) North American will continue to devote most of his or her 1.1-hour travel-time (47) to automobile travel. The very large demand (48) air travel (or high-speed mil travel) that will be manifest in 2050 (49) to only 12 minutes per person a day; a
A. to
B. as
C. with
D. over
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