Short story

                                                 Post-office box
when you have a post-office box,the post man doesn't bring letters to you
 ,but you go to the post-office and get your letters and parcels from your
box.The box is locked,and you have the key ,so thw letters are quite safe.
One day ,the head master of aschool wrote to the post-office and asked
 for a post-office box for his school  .he soon got an answer .it said,'We
will give you a post box in one month.'
Three months later ,...

The head master wrote to the post-office again and
said,'why haven't we got a post box yet?'
This was the answer from post-office .
'Dear Sir,
we gave you a post box two montha ago and wrote to you then to tell
you.here is the key to your box.
You will find our letter to you in it.'