The Ghost

I will tell you a story about something that happened to my friends and me, thirteen months a go.  This is something that I don't wish to happen to any of you, because it was the worst experience of my life.
   It was August 6th, the day of independence of Bolivia.  The day was sunny and all the streets were crowded with people watching the national parade.  I went with some classmates to see the parade, but we never expected to see what we saw.  About ten months before that day, we knew that our math professor in the intermediate school had died.  We were sure about that, because we had sent some flowers to his family the day he died.  We were standing still on the sidewalk watching some pretty high school girls and laughing about some of them hwo used to have a very hard time knowing that ten eyes were looking at them at the same time.  Suddenly we saw the teacher who was dead.  We couldn't believe it, and all of us were afraid; we didn't know what to do or what to say, so we started to run behind him.  While we were running one of my friends asked in a very low tone of voice:
"Could it be a ghost?"  Some started to laugh and others saved their words.  One of us said that we could be wrong, and that we were looking at someone who looked like the teacher.  Finally we reached him, so we started to walk behind him.  When we were face to face, we said, "Hi!" and he said very angrily: "Who are you?", so my friend explained to him that we thought he was our teacher.  The man laughed and said, "Oh! you are talking about my twin brother, you didn't know that he died a bout ten months ago?"  That moment we had to make things easier, so we told him that we didn't know and that we were sorry about that.