题目

“We don’t have rush hours any more”, said Mr. Charles Mac Lean, who runs the nation’s busiest road. “We have rush periods, and they keep getting longer and longer.” Mac Lean was describing Chicago’s 235 miles of expressway. But the same might be said about almost any of the expressways that have become an important part of American city life—and about the heavy traffic that often blocks them. In Chicago, a computerized system has been developed that controls traffic on the city’s seven expressways. Now one man—a controller—can follow the movement of Chicago’s traffic byThe hospital is across _____ the supermarket.              [     ]A. from B. of C. in D. behind