The police at Denver International Airport examined a bomb threat against a United Airlines flight to San Francisco, the flight for hours.
A. delayed
B. to delay
C. delaying
D. had delayed
网友回答
A. delayed
B. to delay
(答案→)C. delaying
D. had delayed
解析：考查分词，现在分词做状语，名词The police和动词delay是主谓关系，所以用现在分词做状语，所以选C