An irate father stormed into the principal's office. ""I demand to know"" he screamed ""why my son Winslow was given a zero on his English examination."" ""Now don't get excited"" said the principal. ""We'll get your Winslow's English teacher in here. I'm sure she has some explanation."" A few minutes later the English teacher arrived. ""Why did you give Winslow a zero on his English final?"" demanded the father. ""I had no choice"" said the schoolmarm. ""He handed in a blank paper with ab…