An adverb is a word or an expression that modifies a verb, adjective, another adverb, determiner, clause, preposition, or sentence. Adverbs typically express manner, place, time, frequency, degree, level of certainty, etc. . They can be used to show how something happens, to what extent, where, and when. Adverbs can also be used to modify entire sentences by expressing a viewpoint or making an evaluation. Adverbs often end in -ly, but not always. Some common examples of adverbs include "really," "very," "well," "badly," "today," "yesterday," "sometimes," "often," "rarely," "early," "late," "here," "there," and "everywhere". Adverbs are considered a part of speech in traditional English grammar and are still included as a part of speech in grammar taught in schools and used in dictionaries.