-ㅆ- makes the past tense, it has -어 after itself. For adjective verbs : 귀여워 - 귀여웠어 괜찮아 - 괜찮았어 For action verbs : 자 - 잤어 봐 - 봤어 To make the perfect tense, you can add -ㅆ던 to the verb. For adjective verbs : 좋은 것 something good 좋던 것 something that was good 좋았던 것 something that has been good 괜찮은 것 something okay 괜찮던 것 something that was okay 괜찮았던 것 something that has been okay Its use slightly differs for action verbs : 자는 사람 someone who sleeps 잔 사람 someone who slept 자던 사람 someone who has slept 잤던 사람 someone who had slept Hope this helps.