Preposition:
* "For" is a preposition when it introduces a phrase that indicates purpose, direction, or time.
* Example: "I went to the store for milk." (Purpose)
* Example: "We walked for hours." (Time)
Conjunction:
* "For" is a conjunction when it connects two clauses, often expressing a reason or explanation.
* Example: "I went to the store, for I needed milk." (Reason)
* Example: "She is a good singer, for her voice is beautiful." (Explanation)
To determine if "for" is a preposition or a conjunction, look at the phrase or clause following it:
* If it is a noun phrase or a prepositional phrase, "for" is a preposition.
* If it is a dependent clause, "for" is a conjunction.