---So hard_ in the past few months that he has made great progress in English. ---I can see that, only a few mistakes _____ in this exam.
The factory has been ________ for two years.
Paris is ______ most beautiful city, where you can see ______ famous Eiffel Tower.
--Where' s Mr Green? --Oh, he _________ Canada.
Beyond _______ stars, the astronaut saw nothing but ________ space.
The headmaster ________for more than two weeks.