P.S. post scriptum. The abbreviation indicates a last-minute addition to a letter or document. Literally, "After what has been written." example : "That's all for now. Take care. Love, John. P.S. Don't forget to write me back!"
i.e. id est. "That is more precisely." Literally, "it is." Commonly used to refine a general statement or provide additional information.
example "Jerry's girlfriend always managed to turn the conversation toward children, i.e., the possibility of having children together; i.e., the possibility of having legitimate children together; i.e., toward the subject of marriage."