Imperfect

The imperfect (abbreviated IMPERF) is a verb form, found in various languages, which combines past tense (reference to a past time) and imperfective aspect (reference to a continuing or repeated event or state). It can therefore have meanings similar to the English "was walking" or "used to walk." It contrasts with preterite forms, which refer to a single completed event in the past.

Traditionally, the imperfect of languages such as Latin and French is referred to as one of the tenses, although in fact it encodes aspectual information in addition to tense (time reference). It may be more precisely called past imperfective.

When used in relation to English, "imperfect" refers to forms much more commonly called past progressive or past continuous (like was doing or were doing). These are combinations of past tense with specifically continuous or progressive aspect.

The term can take on specific conventional meanings in the grammars of particular languages. In German, Imperfekt was used to refer to the simply conjugated past tense (to contrast with the Perfekt or compound past form), but the term Präteritum (preterite) is now preferred, since the form does not carry any implication of imperfective aspect.

"Imperfect" comes from the Latin imperfectus "unfinished", because the imperfect expresses an ongoing, uncompleted action. The equivalent Ancient Greek term was paratatikós "prolonged".

Imperfect meanings in English are expressed in different ways depending on whether the event is continuous or habitual.

For a continuous action (one that was in progress at a particular time in the past), the past progressive (past continuous) form is used, as in "I was eating"; "They were running fast." However certain verbs that express state rather than action do not mark the progressive aspect (see Uses of English verb forms § Progressive); in these cases the simple past tense is used instead: "He was hungry"; "We knew what to do next."

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