Chewing Gum (4)

A doctor once told the American Medical Association that chewing lots of gum helped Jack Dempsey win the heavyweight boxing championship in 1921. He said all the chewing made Dempsey's jaw strong and hard. It was so hard that his opponent broke his thumb when he hit Dempsey's jaw.
Some Americans use ¡®chewing gum¡¯ in a funny expression to joke about someone's lack of . They say the person does not have the mental ability to walk and chew gum at the same time.
  


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