1. Subordinate conjunctions are words or phrases that connect a dependent clause or adjective or adverbial phrase to an independent clause. The dependent clauses provide context and description for the independent clause; in short, it adds information that isn't the direct focus of the sentence but is important in adding time, place, or reasons to the sentence.
2. What subordinate conjunctions do so well is to connect information. Instead of having two short independent clauses that make for a choppy, difficult to read style, subordinate conjunctions allow you to connect sentences, to show relationships, to make your writing flow.
3. As you will notice, when the subordinate conjunction comes at the beginning of a sentence, it nearly always means that a comma will follow soon, usually after the end of that clause..
4. In the following examples, the subordinate conjunctions are italicized.
Ex. 1: After Josie studied the lab reports, she determined that Glen would need further treatment.
Explanation: The After clause explains the time frame for Josie's decision that Glen needed further treatment. It gives readers the information that they need to understand how Josie determined Glen's need. Notice how the above sentence sounds so much better than if the sentence had been written with two independent clauses:
Josie studied the lab reports.
She determined that Glen would need further treatment.
Using a subordinate conjunction to combine the sentences not only makes the style better, but it also tells us that the decision was made after Josie had studied the reports. We can feel better that the decision is based on Josie's previous work and Glen's treatment is not unfounded!
Ex. 2: Because the war is being fought in the Middle East, oil prices will continue to rise.
Explanation: The Because clause provides a reason for the rise in oil prices, the information the writer is stressing in that sentence. Since that clause comes before the main clause, it is followed by a comma. If the clause were to come at the end of the sentence, as in
Oil prices will continue to rise because the war is being fought in the Middle East.
no comma is required.
Ex. 3: Whenever a country goes to war, certain freedoms in that country may be compromised.
Explanation: The main point in the above sentence is that freedoms may be lost; the dependent point, expressed in the whenever clause, gives explanation to the main point by describing when freedoms may be lost. Again notice the comma following the opening dependent clause.
Ex. 4: The candidate, who ran a clean race, was elected by a wide majority.
Explanation: The dependent clause here comes in the middle of the sentence and is used to clarify why the candidate won. Because this who clause can be removed from the sentence without changing the main point, commas are used to separate it from the main clause. Such an unnecessary clause is called a non-restrictive clause since it doesn't restrict the meaning of the sentence.
Ex. 5: Any voters who have registered can vote.
Explanation: In this example, the who clause is necessary to the meaning of the main clause since the meaning of the sentence is that only registered voters can vote. Without who have registered the sentence would have an entirely different meaning. As a result of the necessary clause, there are no commas. Such a clause is called a restrictive clause since it restricts the meaning of the sentence.
Here is a list of common subordinate conjunctions:
Return to OWL, Grammar and Punctuation, or commas.