ㄹ 지도 모르다

Question 1

https://sayhikorean.blogspot.com/2018/09/korean-grammar-expressing-conjecture_43.html

Question 2

집에 없을 수도 있어요 = 집에 없을지도 몰라요 - I MIGHT NOT BE AT HOME

https://funkorean4u.com/2015/05/04/grammar-으ㄹ지도-모르다-maybe/

Question 3

여보, 우산을 가져가세요. 장마철에는 갑자기 비가 올지도 몰라요.
Honey, take an umbrella with you. In the rainy season, it might rain suddenly.

안나 씨가 얼마 전에 산 책을 다 읽었겠지요?
- 요즘 일이 많아서 다 못 읽었을지도 몰라요.
Don’t you think Anna has finished reading the book she bought recently.
- She is very busy these days that she may not have finished yet.

https://www.koreantopik.com/2017/02/l2g07-avn-grammar-might-may-likely.html

Question 4

https://www.topikguide.com/a-v-으ㄹ지도-모르다-korean-grammar/