Roger federer sina sports news (Beijing time) on December 24, the Swiss football legend Roger federer in the New Year at the beginning of the hopman cup back, recently in an interview, he said to himself to win a grand slam always keep the optimistic attitude, will go all out to achieve the goal. Although since 2012, federer can never win the grand slam champion, but when it comes to personal a grand slam title 18, the Swiss think everything...