It was not until she failed in the exam ______she realized the importance of study.
Just wait here, ______ you can hang around for a while. Your turn is half an hour away.
______ Mr. Li is now waiting for you on ______ first floor.
— What do you think of the idea, Jack? — ______ ! I can’t expect a better one.
---- What happened to you? ---- I ________ in the street when someone patted me on the shoulder, which frightened me.
--- How is the man injured in the accident? ---- The doctor said if ________ in a proper way, he was likely to be saved.