conference attending

[r00726]

OFc-18 march
interview -19 march

i have apply the us visa base on conference attending in boston.
morning 9: 00 am my interview after 15 mint. interview then after officer says your visa pending status , they give me green slip (221(g)) and says submit all require document then your visa issue.
i have submit all data 20 march.
after long day no any reply in US embassy
my conference date is 20-21 April.....