I know the password for the user 'sys' and user 'system'

I tried the following when logged in as user 'sys' as sysdba and user
'system' and user 'sys' (normal)

select * from abc.pqr where 'pqr' is a table in schema 'abc'

I get the result

However If I create another user 'test'  and try the following
select * from abc.pqr it gives me the result

ORA-00942: table or view does not exist

I tried the following  when I am logged in as user 'sys' as sysdba or
sysoper or normal or user system

grant select on abc.pqr to test;

The following is the error message

ORA-01031: insufficient privileges