Three days after the aircraft went missing, an international effort ________ ships and planes hasn't found any wreckage, ________ growing frustration for the families of the 239 people on board.
A．involved; causing
B．to involve; caused
C．involving; causing
D．involving; having caused
答案：C
试题分析：考查非谓语动词。句意：飞机失联三天之后，包括船只和飞机在内的国际救援力量尚未发现任何残骸，这让机上239名乘客的家属的心情更加低落。an international effort与involve是主谓关系，即救援力量包括......，应该用现在分词表主动，排除A、B；当两个动作有时间上的先后关系时，需要用分词的完成式，这里的“未找到飞机残骸”和“致使人们更加沮丧”是同时发生的，不需要用现在分词的完成时，排除D，故选C。 考点：考查非谓语动词