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.
What is a verb? A verb is a word that expresses an action or a state of being. As you can see from that definition, there are two main categories of verbs: action verbs and state of being verbs (also known as linking verbs). Because action verbs and linking verbs are strong enough to be used in sentences all by themselves, they are called main verbs.