问题
选择题
Having been attacked by terrorists, _____.
A．doctors came to their rescue
B．the tall building collapsed
C．an emergency measure was taken
D．warnings were given to tourists
答案
答案：B
题目分析：考查非谓语动词。非谓语动词要和主句共用一个主语。只有B的主语能被分词 使用。根据句意其它都不合适。句意：这座大楼被恐怖分子袭击后就倒塌了。根据句意说明B正确。