Therearemanyusefulinventionsintheworld. Haveyoueverwis...
问题详情： Therearemanyusefulinventionsintheworld. Haveyoueverwishedtohaveanumbrellathatmakesyourhandsfree?AlanKaufmanhasthoughtupthe“Nubrella”,whichmeans“new”+”umbrella”isthefirsttrulyhands-fre...