As a general rule, if the subordinating conjunction and associated clause follow the main clause

, do not use a comma. ... An exception occurs when the subordinate clause expresses a contrast, as do clauses beginning with whereas and most clauses beginning with although.

How do you punctuate sentences with subordinating conjunctions?

Subordinating conjunctions that fall in the middle of a sentence are generally not preceded by a comma. This is the opposite of what is done with coordinating conjunctions, or words that join two independent clauses (for, and, nor, but, or, yet, and sometimes so).

How do you use subordinating conjunctions?

A complex sentence will contain a main (independent) clause and one or more subordinate (dependent) clauses which add extra detail or information to the main clause. A subordinating conjunction is the word or words used to join two of those clauses together, words such as because, although, unless, whereas, as soon as.