"They arrived soon after."
The word 'after' is used as :

Question

"They arrived soon after." 
The word 'after' is used as :

Accepted Answer

The word 'after' in the sentence "They arrived soon after." is used as an adverb. Here is a detailed explanation supporting why Option 2 is correct and why the other options are incorrect:

1. **Explanation for Option 2 (Adverb):**
   - In this sentence, 'after' functions as an adverb because it modifies the verb 'arrived' by indicating the timing of the action. Adverbs often provide information about how, when, where, or to what extent an action occurs. In this case, 'after' tells us when the arrival took place, specifically indicating that it happened soon following a previous event or time. This temporal modification is characteristic of adverbial usage.

2. **Why Option 1 (Preposition) is incorrect:**
   - A preposition typically shows the relationship between a noun or pronoun and other words in a sentence, often indicating location, direction, or time. For 'after' to function as a preposition, it would need to be followed by a noun or noun phrase, such as in the phrase "after the meeting." In the given sentence, 'after' stands alone and does not introduce a noun phrase, thus it does not serve as a preposition.

3. **Why Option 3 (Adjective) is incorrect:**
   - Adjectives are used to modify nouns or pronouns, providing more information about them, such as their qualities or quantities. In the sentence "They arrived soon after," 'after' does not describe a noun or pronoun. Instead, it modifies the verb 'arrived,' which is not the function of an adjective. Therefore, 'after' cannot be classified as an adjective in this context.

4. **Why Option 4 (Conjunction) is incorrect:**
   - Conjunctions are words that connect clauses, sentences, or words. Common conjunctions include 'and,' 'but,' and 'or.' In the sentence provided, 'after' does not connect two clauses or sentences. It does not serve to join parts of the sentence together, which is the primary role of a conjunction. Thus, 'after' is not functioning as a conjunction here.

In summary, the word 'after' in the sentence "They arrived soon after." is correctly identified as an adverb because it modifies the verb 'arrived' by indicating the timing of the action, which aligns with the function of an adverb.