Hi I am a SL ,have won a DV 1 visa and a student in UK. Problem is I have 2 more years left for me to complete my degree. DV visa i have to travel to US within 6 months to get it activated. Can i just get my visa activated and come back to UK, then return back .to US. Is there a maximm length i am allowed stay out of US. Also please let me how these will affect my Green card application