Travelers【T1】________into two categories; those who make lists and those who do not. Some people prefer to plan the course of th

Travelers fall into two categories： those who make lists and those who do not. Some people prefer to plan the course of their trip to the finest detail. For others the joy of a trip is its spontaneity.
Neither approach works perfectly in South America. It is an area that requires considerable preparation：internal flights often run only once or twice a week，and an advance booking can mean the difference between continuing to a new city and waiting several days for another flight.