—Must we keep the window open all the time? A. No, you mustn’t B. No, you can’t. C. No, you don’t have to.
Did your father tell you ______?
—I’m afraid that I can’t do it. —Oh, you should believe in yourself. You won’t know what you can do______ you try it.
Before I talked with ______ scientist, I had never met______ clever person like him.
—Thank you for the nice meal you offered us! —_______.
—Are you _______ to go hiking with us? — Yes, I _______.