hi i can't open sony a7s 2 arw files in light room
What exact version of LR are you using? If it is not at least LR CC 2015.2 or LR 6.2 then that camera isn't supported.
You will have to use the newest release of the Adobe free DNG converter program to convert those arw files to DNG and then import them into your version of LR.
Or upgrade your version of LR to the newest release.
Retrieving data ...