He suggested the person referred put into prison.
A. is
B. be
C. should be
D. to be
网友回答
A. is
B. be
C. should be
(答案→)D. to be
解析：考查词组和虚拟语气：主句的谓语是 suggest宾语从句用虚拟语气： that sb. should do sth. 其中that 和should 可以省略。句子中referred to 是过去分词作定语，修饰the person ，be put into prison是宾语从句的谓语部分，省略了should，句意：他建议被提到的人被送进监狱。选D。