up on
 熟悉,精通


 up on
      adj : being up to particular standard or level especially in being
            up to date in knowledge; "kept abreast of the latest
            developments"; "constant revision keeps the book au
            courant"; "always au fait on the latest events"; "up on
            the news" [syn: abreast of(p), au courant, au fait,
             up on(p)]