Let's learn about "커피를 너무 많이 마셨나봐요"

커피를 너무 많이 마셨나봐요 : I must have drunk to much coffee

물을 너무 많이 마셨나봐요 : I must have drunk to much water

밥을 너무 많이 먹었나봐요 : I must have eat to much meal

[other expressions]

- 커피를 너무 마셨나봐. (to the younger people or friends)

- 커피를 너무 마셨나봐요. (honourific by '-요')

- 커피를 너무 마셨나봅니다. (formal; honourific by '-ㅂ')

- 물을 너무 마셨나봐. (to the younger people or friends)

- 물을 너무 마셨나봐요. (honourific by '-요')

- 물을 너무 마셨나봅니다. (formal; honourific by '-ㅂ')

- 밥을 너무 먹었나봐. (to the younger people or friends)

- 밥을 너무 먹었나봐요. (honourific by '-요')

- 밥을 너무 먹었나봅니다. (formal; honourific by '-ㅂ')

[explanations]

* 커피 : coffee

* 물 : water

* 밥 : cooked rice

* -을 : a particle makes 물 / 밥 objective after a word ends in a  consonant

* -를 : a particle makes 커피 objective after a word ends in a  vowel

* 너무 : too much; too many

* 마시다 : drink

* 마셨다 : past tense of 마시다 by '-였-'

* 먹다 : eat

* 먹었다 : past tense of 먹다 by '-었-'

* 마셨나보다 : 마셨(the stem of 마셨다) + -나보다(I think that ~)

* 먹었나보다 : 먹었(the stem of 먹었다) + -나보다(I think that ~)

* a verb + -나봐 : 나보(the stem of 나보다; 보 + -아 contracted into 봐) + -아(a non-honourific descriptive verb ending suffix)

* a verb + -나봐요 : 나보(the stem of 나보다; 보 + -아 contracted into 봐) + -아(a descriptive verb ending suffix) + -요(an honourific ending suffix)

* a verb + -나봅니다 : 나보(the stem of 나보다) + -ㅂ니다(an honourific descriptive verb ending suffix by '-ㅂ')

* ~ㄴ가/은가/는가/나 보다 : guess; think; suppose;  look like; 보다 can be allowed to attached without a space

See https://www.howtostudykorean.com/unit-5/lessons-109-116/lesson-109/

(1) ~ㄴ가 보다 is attached to 이다 and adjectives where the stem ends in a vowel

- 여기가 휴게실인가 봐요 : I guess this is the resting room

- 시험이 어려운가 봐요 : I guess the exam is hard

(2) ~은가 보다 is attached to adjectives where the stem ends in a consonant

그 사람이 싫은가 봐요 : I guess he doesn’t like that person

(3) ~는가 보다 is attached to all verbs and all versions of 있다 and 없다

- 온수가 잘 안 나오는가 봐요 : I guess hot water doesn’t really work (come out) well

- 애기가 지금 욕조에 있는가 봐요 : I guess the baby is in the bathtub

- 그 학생이 자존심이 없는가 봐요 : I guess that student doesn’t have any self-esteem

(4) ~나 보다 can be attached to 이다, adjectives or verbs.

- 시험이 어렵나 봐요 : I guess the exam is hard

- 그 사람이 싫나 봐요 : I guess he doesn’t like that person