Explanation of Complex Sentences with the Help of Examples

When a complex sentence begins with a conjunction such as when, as, because, though, etc., a comma should be placed at the end of the dependent clause. Don't use a comma when the sentence begins with an independent clause.

Example: As she loves to cook, she wants to be a chef.

Sentences are broadly classified into three types: simple, compound, and complex. To be able to differentiate between compound sentences and complex sentences, one should have an understanding of clauses. A clause is a group of related words that contains a subject and a verb.

It shouldn't be confused with a phrase, which is a group of related words that doesn't have a subject-verb combination. Clauses are classified into dependent (Subordinate clause) and independent clauses (Main/Principal clause).

Basically, an independent clause is a standalone sentence, which means that it conveys a complete idea or thought. On the other hand, a dependent clause contains a subject and verb, but it is not a standalone sentence. It needs to be combined with a dependent clause to convey meaning.

Dependent clauses are often joined by conjunctions or relative pronouns. A complex sentence that begins with a dependent clause and ends with an independent clause is referred to as a periodic sentence.

In case of dependent clauses, subordinating conjunctions are placed at the beginning of the clause. These include: As, Since, AS if, After, Because, though, Although, Before, Even though, While, When, Whenever, as soon as, as long as, unless, until, Where, Wherever.

In the following sentences, the dependent clause has been highlighted.

She was still hungry although she ate a big hamburger.

Because the phone kept ringing, she couldn't sleep properly.

The baby cried although she was in her mother's lap.

As the kid was hurt, he started howling.

Because she is pretty, people overlook her flaws.

Although she was angry at him, she still greeted him.

Though she studied very hard for the test, she still failed.

Though the team played well, they lost.

The students studied hard because they knew that the questions wouldn't be easy to answer.
The children devoured the cake because it was delicious.

Because she has stage fright, people are not aware of her singing abilities.

She is going to bed early as she is not feeling well.

I wrote a song while you were away.

When the teacher entered the classroom, the students became quiet.

When she is tired, she is quite irritable.

They spend most of their time on the beach whenever they visit.

She recovered from the infection after she took the medicine.

She must continue to practice until she achieves perfection.

Even though the traffic light turned red, she didn't stop the car.

Though they had lots of money, they were still unhappy.

She returned the dress after she noticed that it was damaged.

I still remember the restaurant where we first met.

The woman, who won the contest, was all smiles.

Although I received the invitation, I am not too keen on meeting them.

The dress, though very expensive, was totally worth it.

As soon as her children arrived, she entered the kitchen to cook their favorite meal.

Even though they arrived late, they didn't seem apologetic.

I don't know when they will come.

Deforestation is an issue that should be resolved.

Here's an example of a complex sentence with two dependent clauses and one independent clause.

Even though he had a medical problem, he studied hard because he wanted to succeed.

An adjective is a word that describes or modifies nouns or pronouns. An adjective clause functions like an adjective, and answers to which, what kind, when (to describe a time), where (describing a place), and why (describing a reason). Who, whom, that, which, whose, when, and where are the relative pronouns that are used in adjective clauses as subordinators. Here are some examples:

This is the project that John submitted.

People who live in glass houses should not throw stones.

Mary bought a necklace that is studded with diamonds.

The house that they live in is not theirs.

The man who had stolen the necklace was caught.

This is the necklace that is made of precious gemstones.

Women who arrived in the morning are fashion models.

An adverb clause functions as an adverb, which means that it modify verbs, adjectives, or other adverbs. It shows relationships such as time, cause and effect, contrast, and condition, and gives answers to when, why, where, how, and to what degree.

Subordinating conjunctions that are used for expressing time in a dependent adverb clause include:

✦ After
✦ Before
✦ When
✦ While
✦ As
✦ Whenever
✦ Since
✦ Until
✦ As soon as
✦ Once
✦ As long as

For showing cause and effect, the following subordinating conjunctions are used:

✦ Because
✦ Since
✦ Now that
✦ As
✦ As long as
✦ So (that)

Subordinating conjunctions that are used for showing contrast include:

✦ Although
✦ Even though
✦ Though
✦ Whereas
✦ While

Subordinating conjunctions that are used for denoting condition include:

✦ If
✦ Unless
✦ Only if
✦ Whether or not
✦ Even if
✦ Provided (that)
✦ In case
✦ In the event (that)

Here are some examples of dependent adverb clauses:

Children watched television after they finished their homework.

Playing chess is fun when you are good at it.

She walked quickly across the street as if she feared for her life.

They will go to the restaurant when the game is over.

She washed the dishes after she finished dinner.

Noun clauses serve as a noun, which means that it can serve as the subject or the object for the verb. It could even be the object of a preposition. Here are some examples:

Whatever you do is fine with me.

I don't remember what I ate for dinner.

Do you know who she is?

I know where he lives.

He ate whatever he could find in the refrigerator.

Everyone knows what the truth is.

We don't know when the guests will arrive.

He will talk to whoever will listen.

Martha didn't listen to what George said.

He wants to learn about whatever is interesting.

The truth is that she cannot cook.

The winner will be whoever finishes the pies first.

If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
― Henry David Thoreau, Walden

The Scarecrow and the Tin Woodman stood up in a corner and kept quiet all night, although of course they could not sleep.
― L. Frank Baum, The Wizard of Oz

Because he was so small, Stuart was often hard to find around the house.
― E.B. White, Stuart Little

He was like a cock who thought the sun had risen to hear him crow.
― George Eliot, Adam Bede

The path to my fixed purpose is laid on iron rails, on which my soul is grooved to run.
― Herman Melville, Moby-Dick

To find out if a sentence is a complex sentence or a compound sentences, you need to identify the independent clause and the dependent clause. In case of a compound sentence, two standalone sentences or independent clauses are joined by a coordinating conjunction.

A simple way to remember the coordinating conjunctions is by way of the mnemonic, FANBOYS (For, And, Nor, But, Or, Yet, So). A sentence that has at least one dependent clause and at least two independent clauses is called a compound-complex sentence. Here are a few examples of compound-complex sentences:

When the earthquake occurred, the windows rattled, and the whole house started shaking.

When she walked the ramp, the other models looked nervous, and people were mesmerized by her beauty.

As soon as the famous singer stepped on the stage, she waved at the crowd, and the crowd cheered.

When the burglar broke in, the alarm went off, and the dog started barking.

Here's an example of a compound sentence:

She waited for the train, but the train was late.

She waited for the train and the train was late are both independent clauses or standalone sentences. These are joined by a coordinating conjunction.

Here's how you can change this compound sentence into a complex sentence:

Because the train was late, she had to wait.
Similarly, you can join two simple sentences with a coordinating conjunction to change it into a complex sentence. Here are some examples:

She went to the movies. She had a test.

She went to the movies even though she had a test.
Mark was recruited. Mark is qualified.

As Mark is qualified, he was recruited.
Her name is Samantha. Samantha is a famous athlete. Samantha lives in New Work.

Samantha, who is a famous athlete, lives in New York.

On a concluding note, a complex sentence can help establish a more specific relationship, when compared to compound sentences. The key to understanding the complex sentence structure is to identify the dependent clause(s), independent clause, and the coordinating conjunction.