1. Preposition: This is the most common use of "after." It introduces a prepositional phrase, which tells us about the time, place, or manner of something.
* Example: "I went to the store after dinner." ("After dinner" is the prepositional phrase, telling us the time of the action.)
2. Adverb: "After" can act as an adverb, modifying a verb, adjective, or another adverb.
* Example: "He arrived after midnight." ("After" modifies the verb "arrived" and tells us when he arrived.)
3. Conjunction: "After" can be a conjunction, connecting two clauses, and showing a time relationship between them.
* Example: "After the rain stopped, we went for a walk." ("After" connects the two clauses and shows that the walk happened after the rain stopped.)
4. Interjection: While less common, "after" can act as an interjection, expressing surprise or dismay.
* Example: "After! I can't believe I lost my keys!" ("After" is used to express surprise and is not grammatically related to the rest of the sentence.)
Therefore, depending on its usage, the word "after" can be a preposition, an adverb, a conjunction, or an interjection.