The water companies were instructed to keep the people ________ to the polluted water．
A.from exposingB.being exposedC.exposingD.from being exposed在线课程D
这题考察词组：keep sb from doing“阻止某人做”，这里的from不能省略，另外be exposed to“暴露于”，句意是：水厂被指示不能让人们接触到污染的水。选D。