Source: Main Street sign, kjelljoran, Flickr
Now that you know the difference between main and subordinate clauses, let’s talk about how you can use them in your writing. When you combine main and subordinate clauses effectively, they create powerful sentences.
Consider the following two sentences.
My father always sets his unicorn traps at night.
He is a superstitious man.
Here we have two perfectly good—albeit strange—sentences. Both are complete thoughts; both are grammatically correct. Taken as a pair, though, they may seem choppy to the reader. We can remedy this by combining the two sentences into one.
Source: Bertuch-Unicorn, Friedrich Johann Justin Bertuch, Wikimedia
My father always sets his unicorn traps at night, and he is a superstitious man.
This gets our point across all right, but what if we want to make it a little more descriptive, a little more interesting? We can accomplish this by subordinating one clause to the other, by emphasizing one thought over another like this:
Because my father is a superstitious man, he always sets his unicorn traps at night.
Changing one of the sentences (He is a superstitious man) to a subordinate clause by adding the subordinating conjunction because not only helps describe the father, but also puts the focus on the second sentence (My father always sets his unicorn traps at night) by making it the main clause.
Let’s practice subordinating one idea to another. In the following exercise, you will be given a sentence starter or the main clause. Your job will be to provide the subordinate clause at the end. Before you begin, here are a couple of things to keep in mind when working with subordinate clauses:
- In general, when a sentence begins with a subordinate clause, it is ALWAYS followed by a main clause, and a comma ALWAYS comes between the two clauses.
- However, if a sentence begins with a main clause, it need not be followed by a dependent clause. If it IS followed by a dependent clause, NO comma is needed between the two clauses.
Using your notes, add a subordinate clause to the following sentence starters. When you are finished, check your understanding to see possible responses. 
Source: Black Cat – Tim,
warriorprincessdi, Wikimedia
- I used to have an old fighting tomcat.
- She lived in a small frame house with her sick mother.
- The country boy was embarrassed and would say nothing.
- I used to have an old fighting tomcat who would get into fights with other cats in the neighborhood.
- She lived in a small frame house with her sick mother because she needed to care for her.
- The country boy was embarrassed and would say nothing although he knew the details of what had happened.
It’s OK if your sentences are different than the sample ones. The idea is that as you read different kinds of sentences containing main and subordinate clauses, you become better able to combine your own ideas in interesting ways.
In the next exercise, let’s practice combining two independent clauses to make a sentence that has both a main and a subordinate clause. You will need to provide a subordinating conjunction in order to join the two independent clauses. Remember, if you begin the sentence with a subordinate clause, a comma will follow it. Again, use your notes to record your answers, and then check your understanding when you’re finished.- He headed to the locker room to get his gym bag.
Zeke finished his workout.
- Lori spent two hours studying for her algebra test.
She wants to maintain her A average.
- My mother waited patiently in the waiting room.
The orthodontist adjusted my braces.
- After Zeke finished his workout, he headed to the locker room to get his gym bag.
- Lori spent two hours studying for her algebra test because she wants to maintain her A average.
- My mother waited patiently in the waiting room while the orthodontist adjusted my braces.
In our last activity in this section, you will read a model sentence; then combining the ideas that follow, you will write a new sentence that is similar in structure to the model.
Here’s an example. Note the subordinating conjunction and the subordinate clause in italics.
Model sentence: Reggie’s first question, when he reached the hotel, was about his friend.
- This is about Tabitha’s favorite activity.
- Her favorite activity is to be on the Internet.
- This happens after she starts up her computer.
New sentence: Tabitha’s favorite activity, after she starts up her computer, is to be on the Internet.
Now, you try it. Use your notes to create a new sentence using the model sentence as a guide. When you are finished, check your understanding to see possible sentences. - Model sentence: When she was home from her boarding school, I used to see her almost every day.
- Something happened while Lucy was making lunch.
- What happened was that her daughter colored on the wall.
- Her daughter used a marker.
- Model sentence: Mrs. Martinez took her class to a dry riverbed when they studied fossils.
- The landscaper inspected the front of the garden.
- The downpour had washed away many things.
- What it washed away was many of the new plants.
- While Lucy was making lunch, her daughter colored on the wall with a marker.
- The landscaper inspected the front of the garden where the downpour had washed away many of the new plants.
If you practice these kinds of activities, you will notice that you are writing longer and more complex sentences, which will add interest to your essays.