아.. 그렇군요 [Ah.. geu-reo-kun-yo] *Oh.. (It is) so. If you wanna say it to younger person or friend, 아.. 그렇구나 [Ah.. geu-reo-ku-na]

to older : "Oh(아-Ah)... i see(알-Al 겠-get 습-sup 니-ni 다-da.)" to younger: "Oh(아- Ah)... i see(알-Al 겠-get 어-er)"