Help!!! how to open .mdf n .mds files?

Cchen

after dowload games, how to open it's .mdf n .mds files?tvb now,tvbnow,bttvb, U' y6 R8 G) h# u5 |
i cant open it?
+ x4 i+ H& G) U$ @! u9 ppls teach me...
& I( m- J" n. z+ Vtvb now,tvbnow,bttvbtq...