6．Plan to get to the airport at least an hour early，or two during holidays and other busy times； this will reduce the stress of the flight．If all goes well，you will have time to relax，shop for last-minute items，or have a meal before the flight．
Flight Delays
Find out why your flight is delayed．Call the free call numbers．Find out if other airlines are experiencing similar delays．If you believe the delay is due to something other than weather or air traffic problems，then mention your suspicion （怀疑） and ask the airline agent to book you on the next available flight，either on the same air-line or a competing one．This is called"Rule 240"，and all airlines are required to do it．
Flight Cancellations （取消）
If your flight is canceled，then make a reservation（预订）on the next flight to your destination．Usually，air-line personnel（职员） will try to book everyone on their next flight．Often they will put you on a competitor's next flight only if you request it．
If on-time arrival is important to you，when you check flights through our reservation system you can rate your choices based on their on-time arrival records．Be sure to also check the weather conditions，as they often affect flight schedules．
21．A person goes to the airport ahead of time mainly toD．
A．buy what he wants in the airport
B．have a good rest in the airplane
C．get on the airplane immediately
D．reduce the pressure of the flight
22．If a person calls"Rule 240"，he wants toD．
A．ask the reason for the plane delay
B．make sure the time for the next plane
C．know if other flights'delays happen
D．change for the ticket to the next flight
23．What would be the best title for the passage？C
A．Unpleasant travels
B．Dangerous flights
C．Airport travel tips
D．Busy airport．
分析 本文是一篇广告布告类阅读，文章主要讲述关于航班的相关知识．首先是提早到达机场；航班延误可以使用240规则；航班取消就要定下一班机；根据目的地的不同等候时间也不同．
解答 21-23 DDC
21．D 细节理解题．根据第一段Plan to get to the airport at least an hour early，or two during holidays and other busy times； this will reduce the stress of the flight．可知提早到达飞机场，可以减轻航行的压力，故选D．
22．D 细节理解题．根据第二段Dask the airline agent to book you on the next available flight，either on the same air-line or a competing one．This is called"Rule 240"，可知要航空局给你定另一班机，要么是相似的航线或其他航线，这就是Rule 240，由此可知Rule 240就是想要得到其他航班的票，故选D．
23．C 推理判断题．根据第一段Plan to get to the airport at least an hour early，or two during holidays and other busy times； this will reduce the stress of the flight．可知计划提前一个小时到飞机场，这将减少坐飞机的压力；和文中的第一个标题Flight Delays 文中的第二个标题Flight Cancellations （取消）．可知文章讲的是飞机旅行的一些建议．故选C．
点评 本文考察学生的理解推断能力以及细心程度，只要抓住文章的关键词，采用寻读的方法查找细节，就能找到正确答案．
