In Japanese, the basic verb form is an imperfective aspect.

The imperfective aspect depicts an action that is still going or underway.

This distinction is actually one of perfective vs. imperfective aspect.

The imperfective aspect was used to describe continuous, durative actions.

This fusion can occur because the imperfective aspect only exists in the past tense.

The tenses of the imperfective aspect are present, imperfect, and future tense.

Verb forms in the imperfective aspect express an action that has (or had) not been completed.

The table below is showing 5 verbs both in their perfective and imperfective aspects.

The imperfective aspect does not present the action as finished, but rather as pending or ongoing.

This is the essence of the imperfective aspect.

The imperfective aspect may be fused with the past tense, for a form traditionally called the imperfect.

Imperfective aspect: indicating an ongoing, continuous, or repeated action.

There is no grammatical marker in Thai for the perfective/imperfective aspect.

The terminology around the stative, perfective and imperfective aspects can be confusing.

The imperfective aspect of the past is used when the speech refers to past situations that were not finished yet, or incomplete.

Usage of the perfective aspect follows the same pattern as the imperfective aspect.

The Indo-Iranian family, for example, shows a split between the perfective and the imperfective aspect.

The infinitive, synoikidzein, is in the imperfective aspect, meaning literally "to live continuously in the same house."

There is a perfective/imperfective aspect distinction.

Unlike the imperfective aspect, inflection does not deviate from conjugation to conjugation.

Proto-Indo-European also used reduplication for imperfective aspect.

They may also denote a temporary state (imperfective aspect), in the case of stative verbs which do not use progressive forms (see below).

The most fundamental aspectual distinction, represented in many languages, is between perfective aspect and imperfective aspect.

The past contrasts perfective and imperfective aspect, and some verbs retain a perfective-imperfective contrast in the present.

However, on the contrary of regular verbs, when the base form is used alone it represents the imperfective aspect and not the perfective aspect.