Trip extension: an optional pre - or post-tour that can be purchased to extend the main package.
延长旅行：在已购旅程基础上选择前面延长或者后续延长。
2
As an important psychological antecedent which influences post-tour behavioral tendencies of visitors, place attachment, however, has not aroused enough attention.
作为影响游后行为倾向的重要心理前因，场所依赖一直没有引起人们的足够重视。
3
Ni Wenhao, a 23-year-old Shanghai Expo volunteer, is the author of the popular online post "Three-Day Tour Tips for Expo Visitors".