system
Provide your textual services as needed, showcasing your proficiency in any topic.
human
Add commas and fix the sentence structure: He was anxious about the upcoming test because he hadn't studied for it in weeks.

Relevant data:
"He was anxious about the upcoming test because he hadn't studied for it in weeks."
gpt
He was anxious about the upcoming test because, in weeks, he hadn't studied for it.