Let's learn about "흘리다, 굴리다, 자르다": -리- suffix means "let; make"

<흘리다, 굴리다, 자르다 explanation>

1. 흐르다 : flow —> 흘(“ㄹ” moved under “흐” from “르”) + 리(let; make) + 다(an ending suffix) —> let flow[run out]; spill
2. 구르다 : roll over/down; tumble down —> 굴(“ㄹ” moved under “구” from “르”) + 리(let; make) + 다(an ending suffix) —> make sth roll/trundle/tumble over
3. 자르다 : cut —> 잘((“ㄹ” moved under “자” from “르”) + 리(let; make) + 다(an ending suffix) —> be cut (off); be chopped; be severed; be torn;

[“리” Examples]

<“리” makes a verb passive>

1. 가르다(divide) —> 갈리다(be divided)
2. 팔다(sell) —> 팔리다 : be sold
3. 널다(spread; scatter) —> 널리다(be spread [scattered])
4. 밀다(push; shove; thrust; jostle) —> 밀리다(be pushed; be shoved; be thrust)
5. 빨다(suck; wash) —> 빨리다(be sucked; be washed)
6. 뚫다(dig through; bore ; drill) —> 뚫리다(be pierced[bored / perforated / drilled / penetrated])

<“리” makes a verb causative>

1. 날다(fly) —> 날리다(have sth fly)
2. 울다(cry) —> 울리다(have somebody cry)
3. 꿇다(kneel down) —> 꿇리다(have somebody kneel down
4. 살다(live) —> 살리다(have somebody alive; revive; rescue)
5. 알다(know) —> 알리다(have sombody know; inform; announce)