"우리 할아버지께서 일하세요."
Translation:My grandfather works.
Haaaaa so this is confusing but really common. Maybe a Korean can explain it better than me but the collective Korean people have an idea of sharing everything so they can say 우리 엄마 to mean my mom, they say 우리 말 to say "in Korean," they say 우리 나라 all the time to say "in Korea."
I don't know about Korean in particular, but in Tagalog, the plural is considered more polite than the singular when speaking with someone higher than you (e.g. your grandfather or something). My guess is that this plays a part in Korean as well, regardless of the historical reasonings for it.
I'm not Korean either, but I think of it like the royal we in English. Not exactly the same, but it's similarly using a plural pronoun in place of a singular.
We just conventionaly use 우리 for represent my...i think especially when i am talk about belongingness
So, in addition to being the Polite Imperative verb ending for regular ~(하)다 verbs, is ~(하)세요 also the standard present tense conjugation for honorific ~(하)시다 verbs?