* Preposition: This is the most common usage. It indicates direction, position, or movement.
* Example: "They walked along the beach."
* Adverb: This usage modifies a verb, adjective, or another adverb, often indicating manner or direction.
* Example: "The train rolled along slowly."
* Adjective: This usage is less common, and it usually refers to something that extends in length.
* Example: "The along road stretched for miles."
It's helpful to look at the context of the sentence to determine which part of speech "along" is functioning as.