Please can you explain 부딪치 changing into 쳤 in this sentence 아야! 머리를 부딪쳤어요 Please can you explain the end of 부딪치 changing into 쳤 in this sentance 아야! 머리를 부딪쳤어요, I am used to seeing 았 or 었 for past tense but this uses ㅕfollowed by ㅆ....Why, what's going on with 부딪쳤어요? I'm confused.