ทบทวนคำที่ใช้ รร (ร หัน)
http://elsd.ssru.ac.th/arun_su/pluginfile.php/86/mod_page/content/1/%E0%B8%84%E0%B8%B3%E0%B8%97%E0%B8%B5%E0%B9%88%E0%B9%83%E0%B8%8A%E0%B9%89%20%E0%B8%A3%E0%B8%A3%20%28%E0%B8%A3%20%E0%B8%AB%E0%B8%B1%E0%B8%99%29%20%281%29.pptx