Obama didn’t explain ______ any larger principles have guided him through the historic convulsions of the 2011 Arab Spring.

When will the plane — In half an hour.

Would you like______to the park with me—I’d love to, but I must do my homework first.

Try to_____ at least an hour each day for learning English and you’ll make progress.

The ________ expression on her face suggested she was_________ when he heard the news.