Grammatical aspectIn linguistics, aspect is a that expresses how an action, event, or state, as denoted by a verb, extends over time. Perfective aspect is used in referring to an event conceived as bounded and unitary, without reference to any flow of time during ("I helped him"). Imperfective aspect is used for situations conceived as existing continuously or repetitively as time flows ("I was helping him"; "I used to help people"). Further distinctions can be made, for example, to distinguish states and ongoing actions (continuous and progressive aspects) from repetitive actions (habitual aspect).
Auxiliary verbAn auxiliary verb (abbreviated ) is a verb that adds functional or grammatical meaning to the clause in which it occurs, so as to express tense, aspect, modality, voice, emphasis, etc. Auxiliary verbs usually accompany an infinitive verb or a participle, which respectively provide the main semantic content of the clause. An example is the verb have in the sentence I have finished my lunch. Here, the auxiliary have helps to express the perfect aspect along with the participle, finished.
Imperative moodThe imperative mood is a grammatical mood that forms a command or request. The imperative mood is used to demand or require that an action be performed. It is usually found only in the present tense, second person. They are sometimes called directives, as they include a feature that encodes directive force, and another feature that encodes modality of unrealized interpretation. An example of a verb used in the imperative mood is the English phrase "Go.
Grammatical tenseIn grammar, tense is a that expresses time reference. Tenses are usually manifested by the use of specific forms of verbs, particularly in their conjugation patterns. The main tenses found in many languages include the past, present, and future. Some languages have only two distinct tenses, such as past and nonpast, or future and nonfuture. There are also tenseless languages, like most of the Chinese languages, though they can possess a future and nonfuture system typical of Sino-Tibetan languages.
ParticipleIn linguistics, a participle (; abbr. ) is a nonfinite verb form that has some of the characteristics and functions of both verbs and adjectives. More narrowly, participle has been defined as "a word derived from a verb and used as an adjective, as in a laughing face". "Participle" is a traditional grammatical term from Greek and Latin that is widely used for corresponding verb forms in European languages and analogous forms in Sanskrit and Arabic grammar.
Grammatical categoryIn linguistics, a grammatical category or grammatical feature is a property of items within the grammar of a language. Within each category there are two or more possible values (sometimes called grammemes), which are normally mutually exclusive.
