아직(a-jik, ajik)
Indicates something is still ongoing or expected but not yet completed
When to use
ongoing state, negation for incompletion, questions about status
The nuance
Use 아직 when something is ongoing or not completed yet. It is mainly used in negative or interrogative sentences, rarely in affirmative ones.
벌써(beol-sseo, beolsseo)
Indicates something has happened earlier than expected or time has already passed
When to use
early completion, affirmative surprise, time elapsed emphasis
The nuance
Use 벌써 to emphasize earlier-than-expected completion or that time has passed. It is mainly used in affirmative sentences and conveys surprise or unexpectedness.
이제(i-je, ije)
Indicates a change from the past to a new state starting now or from now on
When to use
state change, new beginning, both affirmative and negative
The nuance
Use 이제 to express a changed current state or a new beginning from now on. It can be used in both affirmative and negative sentences, emphasizing a turning point.