单选题 To prevent flooding in winter the water flowing from the dam is constantly ______ by a computer.
[A] graded [B] managed [C] conducted [D] monitored

【正确答案】 D
【答案解析】大坝情况由计算机进行“监测”应是monitor。grade分级；打分；manage管理；conduct指挥，给…做向导。句意：为了防止冬季发生水灾，流经大坝的水一直由一台计算机监测。