点P（2﹣a，2a﹣1）到x轴的距离为3，则a为[ ]
A． 2
B． ﹣2
C． 2或﹣1
D． ﹣1
答案：C
按服务性质分，现代化的运输业可分为（）和（）。
_______ was most important to her, she told me, was her family.
A. It B. This C. What D As
