________ is known to all, China will be an _______ and powerful country in 20 or 30 years.
He said he ____ an American before.
Eight students ____ ten in our class are League members.
----- When are you _____ your next exams? ----- Next month.
The book-store _____ open until 8 at night every day.
This task is _____ for us. We need ______ people.