问题
选择题
The river smells terrible. People_______ dirty things into it .
A．must stop to throw
B．must stop from throwing
C．must be stopped to throw
D．must be stopped from throwing
答案
答案：D
题目分析：考查推测，must have done表示对对去事情的肯定推测，名词People和动词词组stop from是动宾关系，所以用被动式，句子意思“河水很难闻，人们一定是把脏东西仍在河水里”,所以选D
点评：推测是个难点，must have done表示对对去事情的肯定推测；may have done表示对过去事情的不可定推测