How Complex Sentences are Formed

Last updated: October 28, 2018 at 23:06 pm

gears photoTo recap: The simple sentence is made of one independent clause. Example: The rain was falling.

The complex sentence is made up of one independent clause and one dependent clause. Example: As I was walking to school, the rain was falling.

The sentence above is an example of a complex sentence. It is made up of:

One dependent clause: As I was walking to school.

One independent clause: The rain was falling.

Both word groups above are clauses because they each have a subject and a verb. The first example, however, does not make complete sense by itself:

As I was walking to school…

It depends on the second clause to complete its meaning.

Think about it. If someone says to you “as I was walking to school,” what would you understand? Of course, it would paint of picture of someone walking to school, yet the meaning would not be complete. You would perk your ears up an anticipation, and probably ask, “yea, as you were walking to school…what happened?”

So then, the dependent clause “as I was walking to school,” although it contains both a subject and a verb, does not form a complete meaning. It “depends” on the independent clause “The rain was falling,” to complete its meaning.

Therefore, the dependent clause “as I was going to school” and independent clause “the rain was falling” combine to form a complex sentence.

What is a dependent clause? A dependent clause “depends” on an “independent clause” to complete its meaning. Dependent means “relying on someone or something.” Independent means “not relying on anyone or anything for completeness, survival etc.”

Think of the sun. We cannot survive without the sun’s energy. But the sun can survive without us. The sun is independent of us, but we are dependent on the sun.

In the same way, a dependent clause does not make sense by itself, it “depends” on the independent clause to complete its meaning. The independent clause, like the sun, can “survive” without the dependent clause and form a complete meaning on its own.

In summary:

Dependent clause: word group that contains both a subject and verb but does not have a complete meaning.

Independent clause: word group that contains a subject and a verb and forms a complete meaning.

Conjunction: joins dependent clause to independent clause to form a complex sentence.

In the complex sentence below, the conjunction “as” joins the dependent clause to the independent clause.

As I was walking to school, the rain was falling.

However, it is not always obvious to see the conjunction joining the two clauses. In fact, if we look at the two clauses above, we can see a comma separating them instead of a conjunction joining them!

Nevertheless, the conjunction “as” does join those two clauses. To demonstrate this, we will reposition the two clauses.

The rain was falling as I was walking to school.

The above is the same sentence with the clauses repositioned. Now independent clause comes first, and the dependent clause comes second. The comma is removed and the conjunction “as” joins these two clauses.

Here are some examples of independent clauses:

1. As he walked out, he saw the police coming.

2. While they were talking, the bomb exploded.

3. Before we walked home, the lightning flashed.

4. When the bandit saw the police, he started to run.

5. If they invite me, I will go.

6. Because of your lies, I will not take you to the promised land.

7. Whenever it rains, I feel cold.

8. Since you are not going, I will go.

9. After the teacher left, the students rejoiced.

10. During the assembly, the students grew impatient.


In all of the examples above, the dependent clause has been placed first and the independent clause second.

Let’s reposition these clauses so that the dependent clauses come first.

  1. He saw the police coming as he walked out.
  2. The bomb exploded while they were talking.
  3. The lightning flashed before we walked home.
  4. The bandit started to run when he saw the police.
  5. I will go if they invite me.
  6. I will not take you to the promise land because of your lies.
  7. I feel cold whenever it rains.
  8. I will go since you are not going.
  9. The students rejoiced after the teacher left.
  10. The students grew impatient during the assembly.

A conjunction joins two clauses in a sentence. A conjunction which joins two independent clause is called a “coordinate conjunction.” A conjunction which joins a dependent clause to an independent clause is called a subordinate conjunction.

The word “subordinate” means “below in rank.” Therefore, think of the coordinate conjunction as the stronger type of conjunction, and think of the subordinate conjunction as the weaker type of conjunction.

The conjunctions used in the complex sentences above are: as, while, before, when, if, because, whenever, since, after, during. Those are all subordinate conjunctions.

Later, when you learn about compound sentences you will examine “coordinate conjunctions” in more detail. A coordinate conjunction joins two independent clauses to form one compound sentence.

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