The present tense is a grammatical tense whose principal function is to locate a situation or event in present time. The term “present tense” is usually used in descriptions of specific languages to refer to a particular grammatical form or set of forms; these may have a variety of uses, not all of which will necessarily refer to present time. For example, in the English sentence My train leaves tomorrow morning, the verb form leaves is said to be in the present tense, even though in this particular context it refers to an event in future time. Similarly, in the historical present, the present tense is used to narrate events that occurred in the past. There are two common types of present tense form in most Indo-European languages: the present indicative (the combination of present tense and indicative mood) and the present subjunctive (the combination of present tense and subjunctive mood). Present tense may be denoted by the glossing abbreviation or .