Using -(으)니까요 and -지요
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I'd like to know if this three phrases are written correctly:

Irregular verb ㅂ in the past answering a question: 시험이 진짜 어려웠으니까요.

Irregular verb ㄹ with -지요: 엄마와 아빠는 브라질에 살지요?

Irregular verb ㄹ with -지요 more formal: 부모님은 브라질에 살시지요?

And, is it possible using them together: -(으)니까지요 ?!

감사합니다!

Question

Using  -(으)니까요 and -지요
언녕하새요!

I'd like to know if this three phrases are written correctly:

Irregular verb ㅂ in the past answering a question:  시험이  진짜  어려웠으니까요.

Irregular verb ㄹ with -지요:   엄마와 아빠는 브라질에 살지요?

Irregular verb ㄹ with -지요 more formal: 부모님은 브라질에 살시지요?

And, is it possible using them together: -(으)니까지요 ?!

감사합니다!

Answer

시험이 진짜 어려웠으니까요 - Correct. ㅂ drops before a vowel, so 어려우니까, 어려웠으니까, etc.

엄마와 아빠는 브라질에 살지요? - Correct.

부모님은 브라질에 살시지요? - Wrong.  살시지요 -> 사시지요 (ㄹ drops before ㄴ, ㅂ, ㅅ, and -ㄹ (사네, 삽시다, 사세요).

-(으)니까지요 ?! - No. You can't combine them.  -니까지요  doesn't make any sense.