These eight expressions are often used when something is being renamed or reiterated:
i.e., that is, e.g., for example, to wit, namely, for instance, in other words
The punctuation depends upon where they are in the sentence and/or what follows them. There are six rules; so we will do a few at a time.
AFTER A QUESTION
Use a question mark after the question, and let the rest stand as its own sentence.
…Where were you that day? That is, June 3.
…Were the two of you there that day? I.e, you and your brother?
Whether you use a period or a question mark at the end depends upon the intonation of the second part.