题目

 His efforts to raise money for his program were ______ because no one showed any intention to take a cent out of their pockets.  A. in place      B. in sight    C. in effect     D. in vain 答案：D某一仪器的读数是指所测的6个位置的刻度的平均值，如果这6个位置在刻度24的两边变动的数据是＋0.3，－0.7，＋0.2，－0.5，＋0.2，－0.4，那么这个仪器的读数应是 [　　] A．23.1B．23.85C．24.15D．24.9