You cannot attach ~고 있다 to adjectives. Adjectives, by their nature, are not able to "progress" as verbs do. This is the same as in English. For example:
저는 행복해요 - I am happy – this is okay.
저는 행복하고 있어요 – I am... being happy? Doesn't make any sense.In English, you can say I am getting happy.

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LEARN KOREAN (한국어) [GRAMMAR] #1
RandomThis is book #1 for the Korean Language series. Try to understand all of the notes in this book before you proceed to the next one. Good luck ! This book contains Korean grammar. Try to understand it so that you can understand how to make a sentence...