Arapça öğretiminde metinler ve okunabilirliğinin Avrupa Ortak Başvuru Metnine göre incelenmesi (Silsiletu'l Lisan ve Menhec el-Alemi B1-B2 Serisi örneği) / Examination of texts and their readability in Arabic teaching books for non-native speakers according to (CEFR) standards: In the intermediate level (B1-B2) of the mother tongue and the global curriculum series as examples