In the past, the Park Service focused on making the big scenic parks more (21) and comfortable for tourists. Roads were paved to allow "windshield visitors" to experience the grandeur of nature without leaving their cars, and a (22) number of hotels and grocery stores were permitted to open (23) the park boundaries.
Now this trend is changing. Plans have been made to (24) the parks to their natural condition as much as possible. The objective of such a move would be to secure the preservation of the parks for future generations, (25) allowing present-day visitors to experience pure wilderness, (26) from any obvious signs of civilization -- an opportunity which is quickly disappearing in the twentieth century. (27) plans call only (28) a reduction in the number of cars (29) into the parks each day, but (30) , tourists may have to leave their cars at the gates and then either visit the park on f
A. in
B. into
C. off
D. through
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