— Hi, Jack, would you like to join us in the sightseeing this weekend?—Thank you, but I regret ______ you that I can’t, for I’m going to visit my grandparents.
Professor Smith, along with his assistants, _____on the Project day and night to meet the deadline.
He met his previous teacher ________ at abroad.
Tom, ______ yourself .Did you forget the school rules?
He is the only one of the students who ______a winner of a scholarship for three years.
Though having lived abroad for years, many Chinese still ______ the traditional customs.