This researcher has a lot of interest in selecting and arranging educational grammatical elements and has tried to systematize them until now. And I argued that grammatical categories should be used actively in the systematization and hierarchization of grammatical elements. And I have published a study on the selection of grammatical elements using grammatical categories. As a part of this study, we used grammatical categories and selected grammatical elements to realize the Tense-Aspect-Modality system. And we arrange the grammatical elements according to the learning stage. For this, chapter 2, I explain the notion of time - related grammar in Korean. We also examined previous works on tense grammar category. Section 3 presents the characteristics of time expression in Korean. And the Tense-Aspect-Modality properties of time expression grammar elements realized by various layers. Section 4 presents the criteria and considerations for selecting time expression grammar elements. Based on this, time - related grammatical elements were finally selected. We also presented the order of arrangement of these elements.