标题: 求解释一道题 [打印本页] 作者: rancetao 时间: 2012-7-12 06:05 标题: 求解释一道题 If A, then B. If B, then C. If C, then D. If all of the statements above are true,which of the following must also be true? (A) If D, thenA. (B) If not B,then not C. (C) If not D,then not A. (D) If D, thenE.（C） (E) If not A,then not D.