—What’s wrong with you, Eric? You look tired.—I ______ to prepare for the final exam last night.
One of the rules is that under no circumstances _______to bring food, drink or chewing gum into the school.
After decades of effort, the city is still trying to _____ how to stop smoking in public places.
Lawmakers have approved the measures_____ protecting the personal information of Web users.
After the war, a new school building was put up ______there had once been a theatre.
Michelle Obama said, “For Barack, success isn't about how much money you make; it's about the______ you make in people's lives.”