The goverment must take measures to prevent the river____.

问题描述:

The goverment must take measures to prevent the river____.
A polluted B polluting C from polluted D being polluted.

D 句型:prevent sb/sth from doing sth 由于河不能自己发出污染的动作只能由别人来实施故要用被动语态,被动语态结构是be + ved由于from要跟ing形式所以是from being polluted.from 常可省略.