In the Korean language adverbs of time are divided into two categories. The first are adverbs dealing with exact time, which mention certain events and actions. The second are adverbs which express a duration of time. These adverbs express a certain period. The former are referred to as `adverbs of a point in time` and the latter as `adverbs of duration`. `Adverbs of duration` are further divided into `moment adverbs` and `continuation adverbs`. The first illustrates only a moment in time, while the second deals with a period of continuous time. This can be illustrated as follows; ◁수식삽입▷ 본문을 참조하세요 When a point of time and duration are expressed by time adverbs, there are three cases: when `ey`(~에) is combined with the preceding noun, when `ey`(~에) is not combined with preceding noun, and when either of these cases applies. For each case, the morpho-semantic properties of `ey`(~에) and the preceding elements, and their co-occurrence relation were considered.