语法与词汇
He _____ the meeting, but upon learning that they would discuss something irrelevant to his field of study, hedropped the idea.
【正确答案】
D
【答案解析】句意：要不他就参加会议了，可是听说要讨论的内容与他的研究领域无关，他就放弃了参加会议的打算。此句是含蓄虚拟条件句，其隐含假设条件是“if he had not learned that…”这种含蓄虚拟句多半是前半部分虚拟，后半部分以but或unfortunately为转折，陈述真实情况，暗指“若不是这种情况存在，就……”。