Complex Sentences

Lesson 4 Complex Sentences

Essential Question

How do we emphasize a complete idea with supporting information?

Grammar in the World

What Do I Know?

Use the interactive exercise below to see how much you already know about complex sentences:

Building Blocks

Grammar is a complex system and structure of language. Mizzou Academy Grammar Lab spotlights one skill (or block) at a time, but it’s often helpful to see how a skill works together with other, related blocks to build the language structure as a whole. You may find the following resource topics helpful as context for this lesson:

Learn About Complex Sentences

A complex sentence is made up of an independent clause and a dependent clause.

Independent Clause: a complete idea with a subject and a predicate (verb) that can stand on its own as a sentence.

I adore big, beautiful fish.

Dependent Clause: contains a subject, predicate (verb), and subordinate conjunction and cannot stand on its own as a complete sentence.

because I adore big, beautiful fish

In a complex sentence:

The independent clause has more weight, or emphasis, than the dependent clause.
The dependent clause gives us more information to support the independent clause.
And, the dependent clause can come first or second in the sentence.

All complex sentences follow these rules:

They contain an independent clause.
They contain a dependent clause.
They contain a subordinating conjunction that introduces the dependent clause.

image courtesy of Canva

Emphasis

For example, consider the two following simple sentences:

I adore big, beautiful fish.

I volunteer at our local aquarium.

First, look at what happens when we choose one of those ideas to be the independent clause and use the other idea to support it.

Because I adore big, beautiful fish, I volunteer at our local aquarium.

I volunteer at our local aquarium because I adore big, beautiful fish.

Next, look at what happens when we emphasize the other clause. Notice how the meaning changes.

Because I volunteer at our local aquarium, I adore big, beautiful fish.

I adore big, beautiful fish because I volunteer at our local aquarium.

In the first example, you emphasize that you love fish, and that resulted in you finding a job at an aquarium. In the second example, you emphasize that you have a job in an aquarium, and that resulted in your love for fish. The way you arrange the ideas in your sentence makes a difference in both the meaning and the emphasis.

Subordinating Conjunctions

First, let’s review the most common subordinating conjunctions. You will use these to introduce a dependent clause in a complex sentence.

There are many subordinating conjunctions; however, there are just five main uses for them.

Subordinating Conjunction	Purpose	Example independent clause dependent clause subordinating conjunction
because, since, as a result, in order that, as, so that	cause and effect	I work at our local aquarium *because* I adore big, beautiful fish.
while, when, once, whenever, before, after	relationship of time	*While* I am in the aquarium, I feel a sense of peace and calm.
where, wherever	relationship of space	My favorite fish follows me with his eyes *wherever* I go.
although, even though, whereas	concession and comparison	*Although* I love fish, I also spend a lot of time with the turtles and frogs.
if, provided that, unless, in case	conditional	If my plans work out, I will become a marine biologist.

Structure

Putting these ideas together into a single complex sentence creates a richer and more complete description of the full experience. We also choose one part of this idea to emphasize. When multiple ideas go together in a meaningful way -- to show a contrast or connection, a cause or an effect, or a qualification, for example -- complex sentences establish and communicate how related ideas connect with one another.

There are two ways to connect independent clauses with dependent clauses to create a complex sentence.

Let’s look again at the sentences you saw in the What Do You Know? The underlined words make up the dependent clause in each sentence. Look carefully. What do you notice about the difference between a dependent clause that comes at the beginning of a sentence and a dependent clause that comes at the end of a sentence?

While Oscar organizes the supplies, Lilia cleans the fish tanks.
Lilia’s favorite fish is the colorful Angelfish although she enjoys the Goldfish and Beta fish, too.
When Oscar gives the dogs a bath, they jump, splash, and try to run away.
Because Lilia and Oscar love these animals so much, they are always happy when a customer adopts one to take home.

image courtesy of Canva

Did you notice that if the dependent clause comes at the beginning of a sentence, it is followed by a comma? If it comes at the end of a sentence, there is no comma.

Dependent Clause + comma when at the beginning of a sentence:	Dependent Clause without comma if at the end of a sentence:
Although most fish take in oxygen from water, the lungfish can break air on land.	The lungfish can breathe air on land although most fish take in oxygen from water.
If there isn’t enough oxygen in their water, fish can drown.	Fish can drown if there isn’t enough oxygen in their water.
Since most fish can only swim in one direction, you’ll never see a fish swim backward.	You’ll never see a fish swim backward since most fish can only swim in one direction.
Wherever it goes, the seahorse swims slowly and upright.	The seahorse swims slowly and upright wherever it goes.
Once you watch Finding Nemo, you’ll know all kinds of interesting facts about fish.	You’ll know all kinds of interesting facts about fish once you watch Finding Nemo.

Use these two equations to help you form complex sentences with independent and dependent clauses:

Dependent Clause + Comma + Independent Clause

- - Even though they live and swim in the water, whales are mammals (not fish).

Independent Clause + No Comma + Dependent Clause

- - Whales are mammals (not fish) even though they live and swim in the water.

Do I Get It?

Use the interactive exercise below to test your knowledge of complex sentences.

Exercise 1: In this first exercise, look at each clause to the right, then drag and drop them to choose whether they are independent or dependent clauses.

Exercise 2: Read each sentence and decide how best to punctuate it.