Questions 17 to 18 are based on the following news. At the end of the news item, you will be given 10 seconds to answer each question. Now listen to the news.
A.Iraq debts. B.WTO talks. C.Financial disasters. D.Possible sanctions.
单项选择题According to Nigel, most problems of air travel are caused by ()
A.unfavorable weather conditions B.airports handling capacity C.inadequate ticketing service D.overbooking