* Adverb: Describing the direction or position relative to something else.
* Example: "The car drove ahead."
* Adjective: Describing something that is in front or in advance.
* Example: "We are ahead of schedule."
* Preposition: Indicating a position in front of or beyond something.
* Example: "He walked ahead of me."
To determine the correct part of speech, you need to analyze how it's being used in a sentence.