239. An adverb answers to a preposition accompanied by a complement.
Example.—Li parolas saĝe = "He speaks wisely," has the same signification as Li parolas kun saĝeco = He speaks with wisdom.
240. Adverbs are used to modify the meaning of verbs, adjectives, or other adverbs.
Examples.—Li agas bone = He acts well. Tiu ĉi estas tre granda domo = This is a very large house. Li skribas treege bone = He writes extremely well.
N.B.—When an adverb seems to qualify a preposition, it really qualifies an adverbial phrase, as:—Multe antaŭ la horo = Much before the time (hour).
241. Position.—Adverbs, as a rule, immediately precede or follow the words which they modify (see par. [88]).
242. There are two classes of adverbs in Esperanto, which for the sake of distinction we will call (a) "Primary" and (b) "Grammatical."
(a). Primary adverbs are all to be found in the list of primary words in [Part V]. They have no distinctive termination.
(b). Grammatical adverbs are those which are formed by adding E to a root, grammatical termination, or affix. Some are formed by adding E to a primary word.
A list of adverbs will be found at [page 166].