이 – if verb ends in vowel or ㅎ 

보다 = to see —> 보이다 = to be seen
바꾸다 = to change —> 바뀌다 = to be changed
놓다 = to place —> 놓이다 = to be placed
섞다 = to mix —> 섞이다 = to be mixed
덮다 = to cover —> 덮이다 = to be covered

내 남자 친구가 날 찼어 – My boyfriend dumped me.
난 차였어 – I was dumped.

히 – if verb ends in ㄷ, ㄱ, ㅈ, or ㅂ

잡다 = to catch —> 잡히다 = to be caught
밟다 = to step on —> 밟히다 = to be stepped on
막다 = to block —> 막히다 = to be blocked
닫다 = to close —> 닫히다 = to be closed
잊다 = to forget —> 잊히다 = to be forgotten

난 아이스크림을 다 먹었어. – I ate all the ice cream.
아이스크림이 다 먹혔어. – All the ice cream was eaten,

리 – if verb ends in ㄹ or ㄷ

열다 = to open —> 열리다 = to be opened
듣다 = to hear —> 들리다 = to be heard
자르다 = to cut —> 잘리다 = to be cut
뚫다 = to pierce —> 뚫리다 = to be pierced

나는 문을 열었어. – I opened the door.
돌아왔을 때 문이 열렸어. – When I came back, the door was open.

개가 우체부를 물었어요 – The dog bit the mailman. (active)
우체부가 개한테 물렸어요 – The mailman was bitten by a dog. (passive)

문이 바람에 열렸어요 – The door was blown open by the wind

기 – if verb ends in ㅁ, ㅅ, ㄶ, or ㄴ

담다 = to fill —> 담기다 = to be filled
잠그다 = to lock —> 잠기다 = to be locked
안다 = to hold —> 안기다 = to be held
씻다 = to wash —> 씻기다 = to be washed
쫓다 = to chase —> 쫓기다 = to be chased

그는 날 안고 있어. – He’s hugging me.
그녀는 안겼어. – She was hugged.