-는군요, -는구나, and -군 grammar = I see that, I didn't realize that ~express surprise

-는군요, -는구나, and -군 grammar grammar = I see that, I didn't realize that, ! ~ express surprise

Usage:
- Express surprise or wonder upon learning something new either from direct observation or experience or hearing = 'I see that', 'I didn't realize that', or '!' in English

- The formal style -는군요 / -군요 is mostly used in books
- The informal style -는구나 / -군 is often used in casual speaking.

Tense:
1. V + 는군요 / -는구나
먹다 --> 먹는군요 / 먹는구나
사다 --> 사는군요 / 사는구나
운동하다 --> 운동하는군요 / 운동하는구나
*만들다 --> 만드는군요 / 만드는구나 

2. A +군요 / -구나 / -군
크다 --> 크군요 / 크구나
덥다 --> 덥군요 /덥구나
피곤하다 --> 피곤하군요 / 피곤하구나

3. N +(이)군요 / (이)구나  / -군
의사이다 --> 의사(이)군요 / 의사(이)구나
학생이다 --> 학생이군요 / 학생이구나




Examples
1. 눈이 나쁘군요.
Your vision is bad indeed.

2. 아이스크림을 좋아하는군요.
You really like ice cream!

3. 감기가 걸렸군요.
I see you have caught a cold.

4. 우산 있어요? 지금 밖에 비가 와요.
- 정말 비가 오는군요. 우산이 없는데 어떻게 하죠?
Do you have an umbrella? It's raining outside now.
- It's really raining! I don't have an umbrella,  what shall I do?

5. 토니 씨, 인사하세요. 이분이 우리 회사 사장님이세요.
- 아, 사장님이시군요. 안녕하세요.
Tony, please say hello. This is our company president.
- Oh, the company president. Nice to meet you.

6. 엄마, 오늘 학교에서 일이 있어서 늦게 왔어요.
- 응, 그래서 늦었구나.
Mom, I was busy at school today, so I came home late.
- Okay. So that's why you're late.

7. 제 여자 친구 사진이에요.
- 여자 친구가 예쁘구나!
It's my girlfriend picture.
- Your girlfriend is beautiful indeed!

8. 점심시간인데 밥을 안 먹어?
-아, 벌써 점심시간이구나!
It's lunch time,  but don't you have lunch?
- Oh, I see it's already lunch time!

9. 벌써 12월이구나!

(I didn't realized that) it's already Dec!

10. 이 섬은 진짜 넓구나!

(I see that) this island is really big!