Thank you for the question. When we use “that” as a pronoun, determiner, adverb, or conjunction, we do not use commas. For example: “That is my book.” (pronoun) “How much is that car?” (determiner) “The fish was that big.” (adverb) “She told him that she liked the class.” (conjunction)
Richard Carrigan has been an educator for over 30 years. He has experience teaching professional and academic English. He earned his graduate degree from Shenandoah University.