SVA sentence

SVA = Subject + Verb + Adverbial

Elephants live here.
Elephants [SUBJECT] live [VERB] here. [ADVERBIAL]

In SVA sentences, the adverbial is required; without it, the sentence is grammatically incomplete:

Elephants live ??

Adverbs and adverbials are optional in the other 6 sentence patterns. You can include adverbials in any sentence you like, but the only sentence pattern that requires an adverbial is the SVA.

AND SEE:
Explanation of adverbs/adverbials
John Seely on the 5+2 sentence patterns
Adverbs at CCC
5+2: the 7 canonical sentence patterns in English
Grammar for Teachers by John Seely

Adverbs and adverbials

VOCABULARY

Adverb refers to “dictionary adverbs”: single words such as slowly or very that are identified as “adverbs” in the dictionary.
Adverbial refers to the adverb function inside a sentence or a phrase. An adverbial can be a single word, a phrase, or a clause:

Rex barked loudly. [SINGLE-WORD ADVERB OR SINGLE-WORD ADVERBIAL]
Rex is barking at the cat. [ADVERBIAL PHRASE]
Rex barks when the postman comes. [ADVERBIAL CLAUSE]

WHAT ADVERBIALS DO INSIDE A SENTENCE

Adverbs (single words) and adverbials (single words, phrases, and clauses) modify everything but nouns, it seems. Adverbs and adverbials modify verbs, adjectives, other adverbs, even entire sentences. John Seely calls adverbs “awkward customers,” and that’s certainly the way I feel about adverbials after reading numerous accounts of adverbs/adverbials and what they do inside a sentence or a phrase.

barks loudly [ADVERB MODIFYING A VERB]
very pretty [ADVERB MODIFYING AN ADJECTIVE]
probably not [ADVERB MODIFYING ANOTHER ADVERB]
Unfortunately, Rex is barking. [ADVERB MODIFYING AN ENTIRE SENTENCE]

Seely writes that “The bulk of [adverbs] provide answers to the questions, ‘When?’ ‘Where?’ and ‘How?’.” Adverbials can also answer the questions, “To what degree?” “How often?” and “Why?”:

Rex was barking this morning. [WHEN]
Rex is barking in the yard. [WHERE]
Rex is barking loudly. [HOW]
Rex is barking very loudly. [TO WHAT DEGREE]
Rex barks constantly. [HOW OFTEN]
Rex barks to tell us the postman has come. [WHY?]

WHERE ADVERBS GO

The great thing about adverbs/adverbials is that they’re relatively moveable:
Rex barked loudly. [AFTER THE VERB]
Rex loudly barked. [BEFORE THE VERB]
Loudly Rex barked. [BEGINNING OF SENTENCE]
Rex was loudly barking. [IN BETWEEN AUXILIARY VERB & LEXICAL VERB]

AND SEE:
Adverbs and other awkward customers – John Seely
Adverbs at CCC
John Seely on the 5+2 sentence patterns
5+2: the 7 canonical sentence patterns in English
Grammar for Teachers by John Seely

‘A new preposition is born’

anything a squirrel can do to a tree
Phyllis Davenport

Anything a squirrel can do to a tree is a memory aid for one group of prepositions, those having to do with location. On the tree, under the tree, beside the tree, and so on.

Here are Rodney Huddleston and Geoffrey K. Pullum on the most common meanings expressed by prepositions (p20):

The most central members of the preposition category have primary meanings expressing various relations of space or time:

across the road
in the box
after lunch
off the platform
at the corner
on the platform
on the roof
before Easter
under the bridge

And here is Geoffrey Pullum on a new preposition being born.

What is a sentence adverb?

The AP Styebook has announced that it will henceforth accept the word “hopefully” as a sentence adverb:

an adverb that affects the meaning of a whole sentence, for example “fortunately” in the sentence “Fortunately, no one was injured.” or “economically” in the sentence “This could be disastrous for the country economically.”
Macmillan Dictionary

When I was a child, I was taught that adverbs modify (“add information to”) verbs.

Walked slowly

Talked loudly

Sang sweetly

And so on.

Between then and now, adverbs have acquired so many roles – as modifiers of verbs, of adjectives, of “determiners,” of other adverbs, of phrases, of sentences – that I sometimes think of the adverb as any modifier that is not an adjective.

I don’t know whether “any modifier that is not an adjective” is a reasonable definition, but when I find out, I will let you know.

Hopefully [SENTENCE ADVERB], that won’t be too long from now.