Let's learn about "어제 결석했어"

(나) 어제 결석했어 : I was absented from the class yesterday

[other expressions]

- (나) 어제 결석했다. (to younger people or friends)

- (나) 어제 결석했네. (to younger people or friends)

- (나) 어제 결석했어. (to younger people or friends)

- (나) 어제 결석했네요. (honourific by '요'; but this had better be used to younger people or friends)

- (저) 어제 결석했어요. (honourific by '요')

- (저) 어제 결석했습니다. (formal; honourific by '-ㅂ')

[explanations]

* 나 : I (non-honourific word)

* 저 : I (honourific word)

* -는 : a particle makes 나 / 저 subjective after a word ends in a vowel

* 난 : a short form of 나는; this omitted

* 전 : a short form of 저는; this omitted

* 어제 : yesterday

* 결석 : absense; nonattendance

* 결석을 하다 = 결석하다 : be absent (from); absent oneself (from); cut; stay away (from); fail to attend; default; make a default

* 결석했다 : past tense of 결석하다 by '-었-'

* 결석했습니다 : 결석하(the stem of 결석하다) + -스(a suffix makes a verb more honourific) + -ㅂ니다(an honourific verb ending suffix by ‘-ㅂ’)

* a verb + -다 / -네 / -어 : a non-honourific descriptive verb ending suffix

* a verb + -네 / -어 + -요 : an honourific verb ending suffix

* a verb + -습니다 / -ㅂ니다 : an honourific descriptive verb ending suffix by '스' / '-ㅂ'