When I teach complex sentences to my students, I use this poster as a reference list for the subordinating conjunctions.
I use the term "glue words" because it is easier to remember and explains what these words do. [Subordinating conjunctions (glue words) are the glue that combine the dependant clause to the independent clause in a complex sentence.
If a sentence begins with a glue word, it needs a comma after the dependant clause to help glue the sentence together. (After she finished the dishes, she swept the floor. - The dependant clause is first; then the independent clause.)
If the sentence has a glue word in the middle, no comma is needed.
(She swept the floor after she finished the dishes. - The independent clause is first; then the dependant clause.)
This poster is also included in a 3-poster package with two other posters: kinds of sentences and conjunctions.