An adjective is a word that describes a noun, and an adverb is a word that describes a verb (or an adjective, another adverb, or phrase). Adverbs vary widely. While most are easy to discern, certain words can function as both adverbs and other parts of speech, requiring you to think them through carefully.
Your best strategy for determining whether a word is an adverb is to look for what that word is modifying, and whether it is answering an adverbial question:
How? When? Where?
(the adverbial questions)
How? (or How much?)
-ly Adverbs
By far the easiest adverbs to spot are the -ly adverbs. They answer the question, “How?” and are formed by taking an adjective and adding the letters `ly` to the end. So “brave” becomes “bravely,” wonderful becomes “wonderfully,” etc. (Some words have a noun version as well, such as the noun “skill,” adjective “skillful,” and adverb “skillfully.”)
”Paul played basketball skillfully.”
“How did Paul play?” He played skillfully.
”Paul barely broke a sweat as he played basketball!”
”I really want to learn how to play like that.”
Here we have the adverbs “barely” (telling us how Paul broke a sweat) and “really” (telling us how much I want to learn).
But don’t get confused with adjectives that end in ‘ly’, like ugly, curly, silly, etc. You can tell a word is an adjective, and not an adverb, by noting two things: (1) it is used to describe nouns (e.g. “the ugly duckling”), and (2) you cannot remove the ‘ly’ to get an adjective (e.g. “ug” is not a word).
Degree
Like adjectives, adverbs can have degrees. Adverbs in the comparative and superlative degree answer the “How much?” question.
”He ran fast. He stands tall. He shoots far.”
(positive adverbs)
”He ran faster. He stands taller. He shoots farther.”
(comparative adverbs)
”He ran fastest. He stands tallest. He shoots farthest.”
(superlative adverbs)
When? (or How often?)
This would include adverbs like “now,” “early,” “recently,” and “daily,” but that is not all.
Noun Adverbs
A noun adverb (aka “adverbial noun”) is a noun acting like an adverb and can also be used to answer the adverbial question “When?”
”Paul played yesterday.”
”Yesterday” is a noun. However, in the context of this sentence, it is modifying the verb “played” and answering the question, “When did Paul play?” Other time-related noun adverbs are “today,” “tomorrow,” etc.
Of course, there are other ways a sentence can answer the “When?” question without using an adverb. Take, for example, the prepositional phrase “at three o’clock.” This is because prepositional phrases usually are acting adverbially. But they are phrases and not adverbs and so diagrammed differently.
The same goes for the “Where?” question.
Where?
Place
Words like “there,” “outside,” “near,” and “south,” are also adverbs.
Paul played basketball outside.
Where did Paul play? Outside. The “outside” is not being played (it’s not receiving the action of the verb); “basketball” is. So “basketball” is the direct object. Other times, “outside” can act as a preposition, but here there is no phrase following the word “outside,” and a preposition is always a part of a prepositional phrase. So we have a simple adverb.
Not!
“Not” is a special adverb that negates the verb (or adjective or adverb) it modifies:
”That basketball hoop is not big.”
”Don't climb the bleachers!”
(the contraction “don’t” contains the negative adverb “not”)