题目

完形填空 I remember quite well a day 17 years ago. That day, our twin sons, Chad and Brad, 1 their car and left home to attend college. I realized that our 2 would soon become a table for two. 3 , the boys would come home on the weekends, but 4 , I knew our family life would never be exactly the same again. The boys walked around each room to 5 they hadn't forgotten anything they needed. I packed a cooler with 6 and their favorite cold snacks. I found a box and filled it with essential 7 items. I thought they might go to bed hungry that night. I 8 my wallet and placed the little bit of 9 I对于实数a，b，c，“a＞b”是“ac＞bc”的(　　) A．充分不必要条件　　　                  B．必要不充分条件 C．充要条件                             D．既不充分也不必要条件