When is a verb be modified with the ~하다 verb ending? I know that you can use ~하다 to modify verbs such as 좋다 and 싫다 to differentiate between an overall like or dislike as opposed to the dis/like of an object. (좋다-> 좋아하다 // 싫다-> 싫어하다) But my question is when the conjugation of a verb 밉다 is changed to 미워하다, or when 그립다 is changed to 그리워하다. There doesn't seem to be a clear answer as to when this change is allowed to take place.