单选题 He left early on the ______ that he had a had toothache and had to see the dentist.

【正确答案】 C

【答案解析】pretext借口，托词；context上下文，前后关系；contest比赛，竞争；prey捕获物，被捕食的动物。句意：他借口牙疼，要去看医生而提前离开。