第33题: [单项选择]All flights ______ because of the typhoon, many passengers could do nothing but wait in the terminal building. A. had been canceled B. have been canceled C. were canceled D. having been canceled 参考答案:D 答案解析:[分析] 此题考查分词独立结构的运用。由于在句子和选项之间没有连词,而且非谓语动词cancel的逻辑主语不是句子的主语passengers,而是flights,因此要用独立结构来表达,四个选项中有三个