The teacher suggested the dictionary at once.A. be referred to be boughtB. be referred to

问题补充：

The teacher suggested the dictionary at once.

A. be referred to be bought

B. be referred to being bought

C. referred to be bought

D. referred to being bought

答案：

A. be referred to be bought

B. be referred to being bought

(答案→)C. referred to be bought

D. referred to being bought

解析：考查虚拟语气和句子结构。本题中的referred to修饰the dictionary,因为两者存在着被动的关系，所以使用过去分词的形式。Suggest（建议）后面的宾语从句使用should+动词原形的虚拟语气，should可以省略。本题在referred to后面省略了should.句意：老师建议被提到的那个字典应该立刻被购买。故C正确。