Another one of my evil tricks

How quickly can you find out what is unusual about this paragraph? It looks so ordinary that you would think that nothing was wrong with it at all, and in fact, nothing is. But it is unusual. Why? If you study it and think about it you may find out, but I am not going to assist you in any way. You must do it without coaching. No doubt if you work at it for long, it will dawn on you. I don't know. Now, go to work and try your luck. Answer