Robots are smart.With their computer brains,they help people work in dangerous places or do difficult
jobs.Some robots do regular jobs.Bobby,the mail carrier,brings mail to a large office building in Washington,
D.C.He is one of 250 mail carriers in the United States.
Mr.Leachim,who weighs two hundred pounds and is six feet tall,has some advantages as a teacher.One
is that he does not forget details.He knows each child's name,the parents' names and what each child knows
and needs to know.In addition,he knows each child's pets and hobbies.Mr.Leachim does not make mistakes.
Each child goes and tells him his or her name,then dials an identification (身份证明) number.His computer
brain puts the child's voice and number together.He identifies the child with no mistakes.Then he starts the
lesson.
Another advantage is that Mr.Leachim is flexible .If the children need more time to do their lessons they
can move switches.In this way they can repeat Mr.Leachim's lesson over and over again.When the children
do a good job he tells them something interesting about their hobbies.At the end of the lesson the children
switch Mr.Leachim off.