Let's learn about "큰일났다"

큰일났어 : (1) I'm in trouble (2) We've got a problem

[other expressions]

- 큰일났다. (to younger people or friends)

- 큰일났네. (to younger people or friends)

- 큰일났어. (to younger people or friends)

- 큰일났군! (to younger people or friends)

- 큰일났구나! (to younger people or friends)

- 큰일났네요. (honourific by '요')

- 큰일났군요! (honourific by '요')

- 큰일났어요. (honourific by '요')

- 큰일났습니다. (formal; more honourific by '스')

[explanations]

* 큰일나다 : become[grow] serious; assume serious proportions; get into trouble

* 큰일났다 : past tense of 큰일나다 by '-었-'

* 큰일났습니다 : 큰일났(the stem of 큰닐났다) + -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 + -군! / -구나! : a non-honourific exclamatory verb ending suffix

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

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