* Period (.) : Used at the end of a declarative sentence (a statement).
* Example: The cat sat on the mat.
* Question mark (?) : Used at the end of an interrogative sentence (a question).
* Example: Did the cat sit on the mat?
* Exclamation point (!) : Used at the end of an exclamatory sentence (a statement showing strong emotion).
* Example: The cat sat on the mat!
There are also less common, but still valid, sentence signals:
* Ellipsis (...) : Used to indicate an incomplete thought, trailing off, or an omitted part of a quotation.
* Example: "I don't know... I just... I need a moment."
* Colon (:) : Used to introduce a list, explanation, or quotation.
* Example: The cat sat on the mat: a soft, furry feline.
It's important to note that these are the primary signals for the end of a sentence. There are some instances where a sentence can be punctuated differently, for example, in dialogue or complex sentence structures.