The story is told about two people named David and Rosy Jackson. Both
of them had very bad memory. For example, Rosy would forget to cook
dinner，or David would go to work on Sunday，thinking it was Monday.
     One winter they were to take a long plane trip. When they arrived at the
airport, there was ten minutes left.In that situation(情况) anyone would get
into the plane right away.But Mr. and Mrs Jackson didn’t do so. They went
to buy the travel first. After they put a two-pound note into a machine , their
insurance policy came out."Who would get the money if the plane crashed,
I wonder?" asked Rosy."My mother，of course. " her husband replied.
"We'll post the policy to her. " Now be quick give me a stamp,will you?"
He said. "The plane is going to take off in a minute. " David put the stamp
on the  envelope, dropped it into a postbox. And suddenly he let out a cry.
What do you think happened to him? He had posted their plane tickets to
his mother.