If you mean the word "at" as a preposition, then it's not usually grammatically correct to end a sentence with it. For example:
* Incorrect: "I'm going to the store, at."
* Correct: "I'm going to the store."
However, there are some exceptions:
* Prepositional phrases: Sometimes, "at" is part of a prepositional phrase that functions as an adverb, which can occur at the end of a sentence. For example:
* "They're waiting for me at the gate."
* "We were all looking at the painting."
* Informal language: In informal speech, it's common to end a sentence with "at", especially in casual conversations or when we're emphasizing a location or time.
If you mean the word "at" as a part of a phrasal verb, then it's perfectly fine to end a sentence with it. For example:
* "I'm looking forward to seeing you at."
* "They got along well at."
It's always best to consider the context and the desired effect of your sentence. If you're unsure, it's generally safer to avoid ending a sentence with "at" as a preposition.