While coordinating conjunctions (and, but, for, nor, or, so, yet), which connect clauses of equal importance, get a great deal of press in every grammar book, they’re not the only conjunctions in town. Subordinating conjunctions connect clauses as well, but theirs is the job of connecting those of unequal importance. Some common subordinating conjunctions are even though, unless, until, because, although, and since.
I find that the problem many people have with these conjunctions is in how to punctuate them. When a clause containing a subordinating conjunction comes before the main clause, a comma should separate them. This isn’t usually a problem.
Note: Remember, the main clause is the independent clause, and the clause with the subordinating conjunction is called the dependent (or, not surprisingly, subordinate) clause.
- Because bacterial pathogens cause disease in plants, we need more information on how plants can resist bacterial pathogens.
Because bacterial pathogens cause disease in plants is the subordinate (dependent) clause that starts with the subordinating conjunction, so it needs a comma before the main (independent) clause.
The problem usually comes when the clause containing the subordinating conjunction (the dependent clause) comes after the main clause. While many people like to add the comma here, too, no comma is needed.
- We need more information on how plants can resist bacterial pathogens because bacterial pathogens cause disease in plants.
Sometimes, it seems that many of us automatically place a comma before certain words, such as because or but or since, without examining how that word is being used in the sentence. This is the grammar equivalent of being on autopilot. What we need to do is to take back the controls and decide the appropriate speed—-I mean comma use.
- Even though RNA replication of the virus already has been studied, there’s more work to be done.
- There’s more work to be done even though RNA replication of the virus already has been studied.
- Since you’ve been gone, I’ve been celebrating.
- I’ve been celebrating since you’ve been gone.