单选题 It was recommended that they ______ for the doctor.
A. has waited B. waited
C. should wait D. should have waited

【正确答案】 C
【答案解析】在“It is+表示提议、要求、命令等含义的动词过去分词+that分句”这一结构中，从句谓语动词用“动词原形”或“should+动词原形”表示虚拟语气。