题目

 He did well in the examination. He _____ hard at his lessons..       A. must have worked     B. can have worked     C. will have worked      D. has worked 答案：A要从已编号（）的枚最新研制的某型导弹中随机抽取枚来进行发射试验，用每部分选取的号码间隔一样的系统抽样方法确定所选取的枚导弹的编号可能是（　　） A         B     C              D