问题
选择题
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
答案
答案：C
题目分析：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
点评：分词是个难点，做分词题时，首先判断名词和动词的关系，由它们的关系确定分词