问题
选择题
The officer demanded that such things ______from happening again.
A．prevented
B．prevent
C．be prevented
D．were prevented
答案
C
题目分析：考查虚拟语气：句意：这个警官要求这样的事情要被阻止再次发生。主句的动词是demand，从句中用虚拟语气，谓语是should do，should可以省略，而且things和prevent是被动关系，选C。