Take another look at the sentence:

Although you might not believe it, Antonio actually benefits from his chicken scratch handwriting because no one can read it, Antonio doesn't have to worry about using the right word or the correct spelling.

Although you might not believe it is a subordinate clause. A subordinate clause cannot stand alone; it must be connected to a main clause. Antonio actually benefits from his chicken scratch handwriting is the necessary main clause. When a subordinate clause introduces a main clause, as in the example above, you must put a comma between the two.

Go back to the sentence to try again.

HomeTermsExercises MOOCHandoutsPresentationsVideosRulesAboutShopFeedback