题目

（2010·黑龙江省哈九中高三三模） 28．The old lady had expected to see all her relatives when she was ill in hospital, but none came to see her ______ many of her neighbors offered their help． A．when               B．as            C．because         D．while 答案：D0.00020080有效数字的个数为（　　） A、9B、8C、4D、5