题目

My grandfather ______ us stories when I was young.       A. was used to tell                   B. is used to telling       C. used to tell                          D. used to telling 答案：C  4．用递等式计算280-（490-390）（209+99）×524578÷6×15                   7000-208×1245×（27+35）（948-196）×14