问题
选择题
(2013·青岛一模)All flights ________ owing to the heavy fog, many passengers could do nothing but take trains.
A．to be cancelled
B．were cancelled
C．have been cancelled
D．having been cancelled
答案
答案：D
选D 考查独立主格结构。逗号前后两部分之间没有连词，因而前半部分不可能是句子，排除B、C两项。此处只能用独立主格结构，动词不定式在此结构中表示将来，故排除A项。现在分词的完成被动式表示被动、完成，故选D项。