[should/ must / might have p.p]

1. must have p.p 

~했나보다. ~했던 모양이야. ~ 했겠다.

너 진짜 배고팠나보다.

You must have been hungry.

(어제 하루종일 아무것도 못먹었어) 너 디게 배고팠겠다.

You must have been hungry.

너 진짜 짜증났겠다.

You must have been frustrated.

그가 결혼했나봐.(=그랬음에 틀림없어)

He must have got married.

2. might have p.p 

~했던 거였을수도 있어.

몸이 갑자기 안좋아졌던 것일 수도 있어.

He might have had some health problems.

~였겠다. 근데 그게 아니라면 ~였을수도 있어.

상사랑 문제가 있었나봐. 근데 그게 아니라면 몸이 갑자기 안좋아졌던 것일 수도 있고.

He must've had some problems with her boss. Either that or, he might have had some health problems.

3. should have p.p 

~했어야만 했는데...(아쉬움)

내가 그를 신뢰했어야 했는데... 그때는 그가 이해되지 않았어.

I should have trusted him, but I didn't understand him at that time.

4. could have p.p 

~할 수도 있었어(아쉬움)

내가 버스를 놓치지 않았으면, 회사에 정시에 도착할 수 있었어.

If I had not missed the bus, I could have arrived at work on time.

could not have p.p 

~했을리가 없어

걔가 일이 질려서 그랬을리가 없어.

He could not have been because he was sick and tired of his job.

제 친구들 중 하나가요. 최근에 일을 그만뒀어요.

글쎄요. 상사랑 문제가 좀 있었나보죠?

그게 아니라면 몸이 갑자기 안좋아졌던 것일 수도 있구요.

어쨌든(어느쪽이든 간에). 걔가 그 일이 질려서 그랬을리가 없어요.

One of my friends recently quit her job.

I don't know, she must've had some problems with her boss.

Either that or, he might have had some health problems.

Either way, he could not have been because he was sick and tired of his job.

~해서 그래.

It's because ~~~ 

더워서 그래.

It's because it's hot.

피곤해서 그래.

It's because it's tried.

출처 : https://youtu.be/uayzRS-3hFs