Before that synonym

Rule 1: You should put a comma before and after “that is” when you are introducing a dependent list of things or information to offer clarification.

• Correct: I am great at cooking Chinese food, that is, sweet and sour chicken and fried rice.
• Incorrect: I am great at cooking Chinese food that is sweet and sour chicken and fried rice.

Rule 2: You should put a comma after “that is” and a semicolon before when it appears before an independent clause.

• Correct: She is a trained sushi chef; that is, she studied at a culinary school in Japan for ten years.
• Incorrect: She is a trained sushi chef, that is she studied at a culinary school in Japan for ten years.

Rule 3: You should not use a comma with “that is” when you use it to specify “what something is” or “why something is.”

In these cases, the term “that is” is essential for the sentence to make sense.

• Correct: I don’t have any money, and that is why I didn’t come.
• Incorrect: I don’t have any money,
  is comma used before that
  is comma needed before that