The simplest answer I can give you is that you will always use some conjugated form - which one will depend on context as you are probably well aware. However, there is one form that is technically conjugated that looks exactly the same as the non-conjugated form. It only applies to adjectives, and it's used in a non-formal present tense way to put more emphasis on the present part of it. The conjugations for that form look like this: If it's a verb, add ㄴ다 if it has a 받침 (a consonant at the end of the last syllable) If it's a verb and doesn't have a 받침 at the end, add 는다 If it's an adjective, just add 다 (this is the exact same as the dictionary/unconjugated form) So, you might for example see someone eat with their friends and exclaim "맛있다!" as opposed to the normal present tense "맛있어!"