A verb is a word that generally conveys an action (bring, read, walk, run, learn), an occurrence (happen, become), or a state of being (be, exist, stand). In the usual description of English, the basic form, with or without the particle to, is the infinitive. In many languages, verbs are inflected (modified in form) to encode tense, aspect, mood, and voice. A verb may also agree with the person, gender or number of some of its arguments, such as its subject, or object. In English, three tenses exist: present, to indicate that an action is being carried out; past, to indicate that an action has been done; and , to indicate that an action will be done, expressed with the or .