How To Determine "Adjective" Or " Adverb" After The Noun? [closed]
The way ahead is busy.
This is the only way possible.
How to determine which one "adjective" and which one "adverb" between "ahead" and "possible"?
Solution 1:
You (or possibly the teachers or the grammar you are working with) are confusing two quite different things: word class ("part of speech") and syntactic function.
As BillJ says, ahead is a preposition and possible is an adjective—that is, those are the word classes into which they are categorized.
But in your sentences both words function as modifiers of a noun. This may not be entirely clear to a learner, because neither is set before the noun it modifies, which is the ordinary position for adnominals.
Possible has its ordinary sense and use. It might with propriety be set before the noun it modifies, the only possible way; but it is one of several adjectives which it is just as proper to set after the noun. In the case of possible this position is licensed by the fact that it frequently takes a following complement (eg, possible to VERB/be VERBen), and adjectives with following complements are required to lie after the noun they modify.
Ahead is employed intransitively, without an object, and therefore acts like a complete preposition phrase. (Etymologically, in fact, it is a preposition phrase, on head.) It is set after the noun it modifies (way) because that is the ordinary position for preposition phrases: compare the way to London, the way from here to there.
Traditional grammar took "part of speech" to be the defining property of words in their syntactic context: for instance, the core function of nouns is to act as subject or object of a verb or object of a preposition, and the core function of adjectives is to modify nouns, either directly or as a predicate complement. Consequently you will often find traditional grammarians categorize entire clauses as "noun phrases" or "adjective phrases" on the basis of their syntactic function. For instance, ahead in this context would be categorized as an "adjective" or "adjective phrase", because it modifies way. In another context (eg, We're looking ahead) it might be categorized as an adverb.
More recent grammars, however, tend to distinguish syntactic function from internal structure and properties; ahead would most commonly be described as a preposition modifying way.