Do you use a comma before while in the middle of sentence?

You don't use a comma before "while" in the middle of a sentence unless it's introducing a contrasting clause.

Here's why:

* "While" as a conjunction: When "while" is used as a conjunction to show simultaneous actions, it doesn't usually require a comma.

* Example: *I was reading a book while my sister was watching TV.*

* "While" as a contrasting conjunction: When "while" introduces a contrasting idea, a comma is used to separate the two clauses.

* Example: *I love to eat pizza, while my brother prefers tacos.*

In short:

* No comma: "While" used as a conjunction showing simultaneous actions.

* Comma: "While" used to introduce a contrasting idea.

Let me know if you have any more questions!