*O Petros exi mia dhaskala stin Veria , ala dhen exi enan dhaskalo stin Katerini .
the Petros has a.F teacher.F in.the Veria but not has one.M (teacher.M) in.the Katerini
(intended) ‘Petros has a female teacher in Veria, but he doesn’t have one (male teacher) in Katerini.