One day I went out and left my key in the house. When I came back I found I couldn't get in without my key. What should I do? After a moment I got an idea. I picked up a big stone and was ready to break the window. Suddenly there came a deep voice "What are you doing?" I turned over and saw a policeman was behind me. It took me quite a long time to explain myself. I won't be so careless again.