Benign paroxysmal positional vertigo is caused by calcium debris in the semicircular canals (canalithiasis), usually the posterior canal. Medications generally are not recommended for the treatment of this condition.
In grammar, tense is a category that expresses time reference. Tenses are usually manifested by the use of specific forms of verbs, particularly in their conjugation patterns. Basic 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.
In some languages, the grammatical expression of past tense is combined with the expression of other categories such as mood and aspect (see tenseâaspectâmood). Thus a language may have several types of past tense form, their use depending on what aspectual or other additional information is to be encoded.