The past tense (abbreviated pst) is a grammatical tense that places an action or situation in the past of the current moment (in an absolute tense system), or prior to some specified time that may be in the speaker's past, present, or future (in a relative tense system).^[1] Not all languages mark verbs for the past tense (Mandarin Chinese, for example, does not); in some languages, the grammatical expression of past tense is combined with the expression of moodand/or aspect (see tense–aspect–mood). Some languages that mark for past tense do so by inflecting the verb, while others do so by using auxiliary verbs (and some do both).