Жалғастыру немесе қайталаудың грамматикалық жағы

Grammatical aspect of continuity or repetition

The imperfective (abbreviated or more ambiguously ) is a grammatical aspect used to describe ongoing, habitual, repeated, or similar semantic roles, whether that situation occurs in the past, present, or future. Although many languages have a general imperfective, others have distinct aspects for one or more of its various roles, such as progressive, habitual, and iterative aspects. The imperfective contrasts with the perfective aspect, which is used to describe actions viewed as a complete whole.

English is an example of a language with no general imperfective. The English progressive is used to describe ongoing events, but can still be used in past tense, such as "The rain was beating down". Habitual situations do not have their own verb form (in most dialects), but the construction "used to" conveys past habitual action, as in I used to ski. Unlike in languages with a general imperfective, in English the simple past tense can be used for situations presented as ongoing, such as The rain beat down continuously through the night. A contrast between the progressive and imperfective is seen with stative verbs. In English, stative verbs, such as know, do not use the progressive (*I was knowing French is ungrammatical), while in languages with an imperfective (for instance, French), stative verbs frequently appear in the imperfective. African American Vernacular English does have an imperfective aspect for present tense formed by adding "be" before the present continuous of a verb, such as "he be working", or "they be eating".

Verbs in Slavic languages have a perfective and/or an imperfective form. Generally, any of various prefixes can turn imperfectives into perfectives;
suffixes can turn perfectives into imperfectives. The non past imperfective form is used for the present, while its perfective counterpart is used for the future. There is also a periphrastic imperfective future construction.

The imperfective aspect may be fused with the past tense, for a form traditionally called the imperfect. In some cases, such as Spanish and Portuguese, this is because the imperfective aspect occurs only in the past tense; others, such as Georgian and Bulgarian, have both general imperfectives and imperfects. Other languages with distinct past imperfectives include Latin and Persian.

The opposite aspect is the perfective (in Ancient Greek, generally called the aorist), which views a situation as a simple whole, without interior composition. (This is not the same as the perfect.) Unlike most other tense–aspect category oppositions, it is typical for a language not to choose either perfective or imperfective as being generally marked and the other as being generally unmarked. This is the essence of the perfective aspect: an event presented as an unanalyzed whole. 'Was reading', however, is different. Besides being the background to 'entered', the form 'reading' presents "an internal portion of John's reading, [with] no explicit reference to the beginning or to the end of his reading." Here each sitting is an unanalyzed whole, a simple event, so the perfective root of the verb 'sat' is used. However, the clause as a whole describes an ongoing event conceived of as having internal structure, so the imperfective suffix eshe is added. Without the suffix, the clause would read simply as In the evening he sat on the veranda.