A man went to see a doctor.“Open your mouth,” the doctor sai

A man went to see a doctor.“Open your mouth,” the doctor said.Then the man opened his mouth and
“ Doctor,you don’t understand,” the man said,“ I ……”
“ I don’t want to hear any excuses,” The doctor said,“ You must find time for exercise.If you don’t,you will get fat and have health problem when you are older.”
“ But I walk every day,” the man said.
“ On,yes,and I know what kind of walking that is.You walk a few feet to the train station from your house,a few more feet from the station to your office,and a few more feet from your office to a restaurant for lunch and back.That’s not real walking.I’m talking about walk in the park for twenty minutes every day.”
“ Will you listen to me,doctor!” the man shouted,getting angry with this doctor who thought he knew everything.“ I’m a postman,” the man went on,“and I walk for seven hours every day.”