Imperfect in the context of Perfect aspect

The past tense is a grammatical tense whose function is to place an action or situation in the past. Examples of verbs in the past tense include the English verbs sang, went and washed. Most languages have a past tense, with some having several types in order to indicate how far back the action took place. Some languages have a compound past tense which uses auxiliary verbs as well as an imperfect tense which expresses continuous or repetitive events or actions. Some languages inflect the verb, which changes the ending to indicate the past tense, while non-inflected languages may use other words meaning, for example, "yesterday" or "last week" to indicate that something took place in the past.

The Polabian language, also known as Drevanian–Polabian language, Drevanian language, and Lüneburg Wendish language, is a West Slavic language that was spoken by the Polabian Slavs (German: Wenden) in present-day northeastern Germany around the Elbe, from which comes the term Polabian. It was spoken approximately until the rise to power of Prussia in the mid-18th century – when it was superseded by Low German – in the areas of Mecklenburg-West Pomerania, central Mittelmark part of Brandenburg and eastern Saxony-Anhalt (Wittenberg originally part of Bela Serbia), as well as in eastern parts of Wendland (Lower Saxony) and Schleswig-Holstein, Ostholstein and Lauenburg). Polabian was also relatively long (until the 16th century) spoken in and around the cities of Lübeck and Oldenburg. The very poorly attested Slavic dialects of Rügen seemed to have had more in common with Polabian than with Pomeranian varieties. In the south, it bordered on the Sorbian language area in Lusatia.

Polabian is characterized by the preservation of a number of archaic features, such as the presence of nasal vowels, a lack of metathesis of Proto-Slavic *TorT; the presence of an aorist and imperfect verb tenses, traces of the dual number, and some prosodic features, as well as by some innovations, including diphthongization of closed vowels, a shift of the vowels o to ö, ü and a to o; a softening of the consonants g, k in some positions to d', t', an occasional reduction of final vowels, and the formation of complex tenses, many which are associated with the influence of the German language. Polabian also has a large number of Middle Low German borrowings.

Ancient Greek verbs have four moods (indicative, imperative, subjunctive and optative), three voices (active, middle and passive), as well as three persons (first, second and third) and three numbers (singular, dual and plural).

• In the indicative mood there are seven tenses: present, imperfect, future, aorist (the equivalent of past simple), perfect, pluperfect, and future perfect. (The last two, especially the future perfect, are rarely used).
• In the subjunctive and imperative mood, however, there are only three tenses (present, aorist, and perfect).
• The optative mood, infinitives and participles are found in four tenses (present, aorist, perfect, and future) and all three voices.

The distinction of the "tenses" in moods other than the indicative is predominantly one of aspect rather than time.