Earlyonemorning,morethanahundredyearsago,anAmericaninve...
问题详情：Earlyonemorning,morethanahundredyearsago,anAmericaninventorcalledEliasHowefinallyfellasleep.Hehadbeenworkingallnightonthedesignofasewingmachinebuthehadrunintoaverydifficultproblem:Itseemedimpo...