يَقُومُ زَيْدٌ
Zayd rises, is rising, or may rise, according to the context.
The Arabic imperfect can accommodate present and future readings. In سَيَقُومُ زَيْدٌ, the future prefix highlights a later event, while an indication such as «الآن» can specify an ongoing present event.
Thus “imperfect = only this exact moment” is too narrow. The source's discussion of three temporal divisions requires separating the broad conventional notion of time from precise chronological boundaries. The verb provides a framework; contextual indicators select a reading.