The simple word ‘so,’ can be a real bear when it comes to punctuation. Do you use a comma before it or not?
Here’s an Easy Way to Know
- If the word ‘therefore’ is used to replace the word ‘so’ and the sentence still works, use a comma.
- If you replace the word ‘so’ with the words ‘so that’ and the sentence still works do not use a comma.
For this I must refer you to grammarlyblog (https://www.grammarly.com/blog/comma-before-so/).
Read my short story: Two Tons For Maria.