问题
选择题
Having been attacked by terrorists, ______.
A．doctors came to their rescue
B．the tall building fell down
C．an emergency measure was taken
D．warnings were given to tourists
答案
答案：B
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。