use the following query


for system privelege
-- - - ------ -- - -- - - - - -- -- --
select role,privelege,admin_option
from role_sys_privs
order by role,privelege;

for object privelege
_ --- -- -- -- -- --- --- --
select grantor,grantee,owner
tablename,privelege,grantable
from dba_tab_privs,dba_roles
where grantee=role
order bt grantee,owner,table_name;

sql will show object priveleges garnted to roles
-- - -- --- -- --- - -- -- --- -- --- -- -- --- - --- ---
select grantor,grantee,owner
tablename,privelege,grantable
from dba_tab_privs,all_users
where garntee=username
order by grantor grantee,owner,table_name;

hope this helps