Question

add or remove commas, if necessary, until the sentence has correct punctuation.
before he joins the chess team shrek wants me to help him practice.

Explanation:

The sentence has two independent clauses related by a time - adverbial clause. The clause "Before he joins the chess team" is an adverbial clause of time, and it should be separated from the main clause "Shrek wants me to help him practice" with a comma to show the correct sentence structure and improve readability.

Answer:

Before he joins the chess team, Shrek wants me to help him practice.