题目：
In the United States, average fuel efficiency of newly manufactured domestic cars, although remaining worse than that of newly manufactured imported cars, substantially improved between 1983 and 1988. Average fuel efficiency of new domestic cars has not improved since, but the difference in average fuel efficiencies of new domestic cars and new imported cars has steadily decreased.
If the statements above are true, which of the following must also be true on the basis of them
A．Average fuel efficiency of domestic cars manufactured after 1988 was better than that of imported cars manufactured before 1988.
B．Average fuel efficiency of newly manufactured domestic cars has steadily worsened since 1988.
C．Average fuel efficiency of newly manufactured imported cars has steadily worsened since 1988.
D．Average fuel efficiency of newly manufactured imported cars has steadily improved since 1983.
E．(E) Average fuel efficiency of imported cars manufactured in 1983 was better than that of imported cars manufactured in 1988.
答案：
参考答案：C
解析： 本题属于数学相关类的归纳题，可以用简单的数学思维去判断。通过读题，发现重点为“新的国产汽车自1988年后平均油效未提高，而与进口汽车的平均油效的差距却减小了”，因此可以得出结论，进口汽车在1988年后的平均油效减小了。所以(C)正确。
