The police at Denver International Airpo
问题:
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
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