单选题Having been attacked by&n

问题补充：

单选题Havingbeenattackedbyterrorists,______.A.doctors came to their rescueB.the tall building fell downC.an emergency measure was takenD.warnings were given to tourists

答案：

B解析考查非谓语动词用法。非谓语动词做状语的条件就是它的逻辑主语必须是句子的主语。本题的非谓语动词为Having been attacked，它的逻辑主语是动作的承受者。只有B的主语是攻击的承受者。故B正确。句意：被恐怖分子攻击以后，这栋高楼倒塌了。