In that country, guests tend to feel they are not highly ______ if the invitation to a dinner party is extended only three or four days before the party date.

单项选择题In spite of the wide range of reading material specially written or ______ for language learning purposes, there is yet no comprehensive systematic program for the reading skills.

单项选择题But in our enthusiasm to discover our heritage, we are ruining the very scenery we go to enjoy, damaging natural habitats, ______ down footpaths, disturbing wildlife, polluting the air and dropping litter.