Mastering Complex Sentences: Definition, Usage, and Examples

Complex sentences are a cornerstone of sophisticated English writing and communication. Understanding how to construct and use them effectively allows you to express nuanced ideas, establish clear relationships between different parts of your message, and create more engaging and persuasive content.

This article provides a comprehensive guide to complex sentences, covering their definition, structure, types, usage rules, common mistakes, and advanced applications. Whether you’re an English language learner, a student honing your writing skills, or a professional seeking to improve your communication, this guide will equip you with the knowledge and tools you need to master complex sentences.

Table of Contents

• Introduction
• Definition of Complex Sentences
• Structural Breakdown of Complex Sentences
• Types of Clauses in Complex Sentences
• Examples of Complex Sentences
• Usage Rules for Complex Sentences
• Common Mistakes with Complex Sentences
• Practice Exercises
• Advanced Topics in Complex Sentences
• Frequently Asked Questions (FAQ)
• Conclusion

Definition of Complex Sentences

A complex sentence is a sentence that contains one independent clause and at least one dependent clause. An independent clause can stand alone as a sentence because it expresses a complete thought. A dependent clause, on the other hand, cannot stand alone as a sentence because it does not express a complete thought, even though it contains a subject and a verb. Dependent clauses are often introduced by subordinating conjunctions or relative pronouns, which connect them to the independent clause.

The primary function of a complex sentence is to show the relationship between ideas. The dependent clause provides additional information, context, or explanation for the idea expressed in the independent clause.

This can help to create more nuanced and detailed writing.

Complex sentences are used in various contexts, including academic writing, professional communication, and creative writing. They allow writers to convey complex ideas with clarity and precision, and to establish logical connections between different parts of their arguments or narratives.

Understanding complex sentences is crucial for effective communication in both written and spoken English.

Structural Breakdown of Complex Sentences

The basic structure of a complex sentence involves an independent clause and one or more dependent clauses. The order of these clauses can vary, affecting the emphasis of the sentence.

The dependent clause can come before or after the independent clause.

Independent Clause

An independent clause contains a subject and a verb and expresses a complete thought. It can stand alone as a sentence.

For example: “The dog barked.”

Dependent Clause

A dependent clause also contains a subject and a verb, but it does not express a complete thought. It relies on the independent clause for its meaning. Dependent clauses are introduced by subordinating conjunctions (e.g., because, although, if, when, since) or relative pronouns (e.g., who, which, that). For example: “Because it was raining.”

Subordinating Conjunctions

Subordinating conjunctions connect a dependent clause to an independent clause. They indicate the relationship between the two clauses, such as cause and effect, time, condition, or contrast.

Some common subordinating conjunctions include: after, although, as, because, before, even if, even though, if, since, so that, than, though, unless, until, when, where, while.

Relative Pronouns

Relative pronouns introduce relative clauses, which are a type of dependent clause that modifies a noun or pronoun in the independent clause. Common relative pronouns include: who, whom, which, that, whose.

Clause Order

The order of the clauses in a complex sentence can affect the emphasis and flow of the sentence. If the dependent clause comes first, it is usually followed by a comma.

If the independent clause comes first, a comma is generally not needed.

• Dependent Clause + Comma + Independent Clause: Because it was raining, the game was cancelled.
• Independent Clause + Dependent Clause: The game was cancelled because it was raining.

Types of Clauses in Complex Sentences

Dependent clauses can be categorized into three main types: adverbial clauses, adjective clauses (also known as relative clauses), and noun clauses. Each type serves a different function within the complex sentence.

Adverbial Clauses

Adverbial clauses modify the verb, adjective, or adverb in the independent clause. They provide information about time, place, manner, cause, purpose, condition, or result.

Adverbial clauses are introduced by subordinating conjunctions.

Examples:

• Time: When the bell rings, the students will leave.
• Place: You can sit wherever you like.
• Manner: He spoke as if he knew the answer.
• Cause: Because it was cold, I wore a coat.
• Purpose: I study hard so that I can get good grades.
• Condition: If it rains, we will stay inside.
• Result: It was so hot that I had to take a shower.

Adjective Clauses (Relative Clauses)

Adjective clauses modify a noun or pronoun in the independent clause. They provide additional information about the noun or pronoun.

Adjective clauses are introduced by relative pronouns (who, whom, which, that, whose) or relative adverbs (where, when, why).

Examples:

• The book that I borrowed from the library is very interesting.
• The man who helped me is my neighbor.
• This is the house where I grew up.

Noun Clauses

Noun clauses function as nouns in the independent clause. They can be used as subjects, objects, complements, or appositives.

Noun clauses are introduced by words like that, what, who, whom, which, whoever, whomever, whichever, whether, if, and how.

Examples:

• What he said surprised everyone. (Subject)
• I don’t know what he wants. (Object)
• The question is whether we should go. (Complement)
• My belief, that honesty is the best policy, guides my actions. (Appositive)

Examples of Complex Sentences

This section provides extensive examples of complex sentences, organized by the type of dependent clause used. Each table contains numerous examples to illustrate the different ways complex sentences can be constructed and used.

Examples with Adverbial Clauses

The following table presents examples of complex sentences using different types of adverbial clauses, including time, place, cause, condition, and purpose.

Type of Adverbial Clause	Example Sentence
Time	After I finish my work, I will go to the gym.
Time	I always feel sleepy when it rains.
Time	Before you leave, make sure to lock the door.
Time	She started singing as soon as the music began.
Time	We will go to the park until it gets dark.
Place	You can sit wherever you find a chair.
Place	I will follow you wherever you go.
Place	They built their house where the old oak tree stood.
Place	He left the keys where I could easily find them.
Place	We decided to picnic where the view was best.
Cause	Because I studied hard, I passed the exam.
Cause	She was late since her car broke down.
Cause	As it was getting late, we decided to go home.
Cause	They canceled the game because of the rain.
Cause	He was happy because he received a promotion.
Condition	If it rains, we will stay inside.
Condition	I will help you if you need it.
Condition	Unless you study, you will not pass the exam.
Condition	She will succeed if she works hard.
Condition	Provided that you pay on time, you can renew your membership.
Purpose	I exercise regularly so that I can stay healthy.
Purpose	He saved money in order to buy a house.
Purpose	She studied English so that she could travel abroad.
Purpose	They practice every day so that they can win the competition.
Purpose	I am writing this letter so that you are aware of the situation.
Manner	He acted as if he were the boss.
Manner	She decorated the cake as she had seen in the magazine.
Manner	They treated him as if he were a celebrity.
Manner	He explained the concept as if he was speaking to a child.
Manner	She sang as beautifully as an angel.

Examples with Adjective Clauses (Relative Clauses)

The following table presents examples of complex sentences using adjective clauses, which modify nouns or pronouns in the independent clause.

Relative Pronoun/Adverb	Example Sentence
Who	The man who helped me is my neighbor.
Who	The students who studied hard passed the exam.
Who	The woman who wrote the book is a famous author.
Who	My friend who lives in New York is visiting me next month.
Who	The people who attended the meeting were very interested.
Whom	The person whom I admire most is my mother.
Whom	The candidate whom they selected is highly qualified.
Whom	The artist whom everyone praised was very humble.
Whom	The student whom the teacher recommended received a scholarship.
Whom	The employee whom the manager promoted was very dedicated.
Which	The book which I borrowed from the library is very interesting.
Which	The car which he bought is very expensive.
Which	The movie which we watched last night was amazing.
Which	The cake which she baked was delicious.
Which	The song which they played was very popular.
That	The house that I want to buy is near the park.
That	The food that she cooked was very tasty.
That	The idea that he suggested was brilliant.
That	The problem that they faced was very challenging.
That	The project that they completed was very successful.
Whose	The student whose essay won the prize is very talented.
Whose	The author whose book I read is very inspiring.
Whose	The company whose products are popular is very innovative.
Whose	The family whose house burned down received a lot of support.
Whose	The artist whose paintings are famous is very creative.
Where	This is the restaurant where we first met.
Where	The city where I grew up is very beautiful.
When	I remember the day when we first met.

Examples with Noun Clauses

The following table presents examples of complex sentences using noun clauses, which function as nouns in the independent clause.

Function of Noun Clause	Example Sentence
Subject	What he said surprised everyone.
Subject	How she did it remains a mystery.
Subject	Whatever you decide is fine with me.
Subject	That he is innocent is now clear.
Subject	Whether it will rain is uncertain.
Object	I don’t know what he wants.
Object	She didn’t understand why he left.
Object	They discussed how to solve the problem.
Object	He asked if I was coming.
Object	We will see who wins the game.
Complement	The question is whether we should go.
Complement	My concern is that we will run out of time.
Complement	His excuse was that he missed the bus.
Complement	The problem is how to get there.
Complement	Her fear is that she will fail the test.
Appositive	My belief, that honesty is the best policy, guides my actions.
Appositive	The rumor, that he is retiring, may not be true.
Appositive	His idea, that we should start early, is a good one.
Appositive	The fact, that she is talented, is undeniable.
Appositive	The hope, that things will get better, keeps us going.

Usage Rules for Complex Sentences

Using complex sentences correctly involves understanding the rules of punctuation, subject-verb agreement, and pronoun reference. Proper usage ensures clarity and avoids grammatical errors.

Punctuation Rules

When a dependent clause comes before an independent clause, a comma is usually required after the dependent clause. When the independent clause comes first, a comma is generally not needed unless it is required for clarity or to avoid misreading.

• Dependent Clause First: Because it was raining, the game was cancelled.
• Independent Clause First: The game was cancelled because it was raining.

Subject-Verb Agreement

Ensure that the verb in each clause agrees with its subject in number (singular or plural). This is particularly important in complex sentences where there are multiple subjects and verbs.

• Correct: Because he studies hard, he gets good grades.
• Incorrect: Because he study hard, he gets good grades.

Pronoun Reference

Make sure that pronouns have clear and unambiguous references. The pronoun should clearly refer to a specific noun or pronoun in the sentence or previous sentences.

• Clear: The teacher praised the student because he had worked hard. (He refers to the student.)
• Unclear: The teacher praised the student because he was helpful. (It’s unclear who he refers to.)

Avoiding Sentence Fragments

Ensure that the dependent clause is always connected to an independent clause. A dependent clause standing alone is a sentence fragment and is grammatically incorrect.

• Fragment: Because it was raining.
• Correct: Because it was raining, the game was cancelled.

Using Correct Subordinating Conjunctions and Relative Pronouns

Choose the appropriate subordinating conjunction or relative pronoun to express the intended relationship between the clauses. Using the wrong word can change the meaning of the sentence or make it nonsensical.

• Incorrect: Although it was raining, I took an umbrella.
• Correct: Because it was raining, I took an umbrella.

Common Mistakes with Complex Sentences

Several common mistakes can occur when using complex sentences. Understanding these errors can help you avoid them and improve your writing.

Comma Splices

A comma splice occurs when two independent clauses are joined together with only a comma. This is incorrect and should be avoided.

Incorrect	Correct	Explanation
The game was cancelled, it was raining.	The game was cancelled because it was raining.	The two independent clauses are incorrectly joined with just a comma.
She studied hard, she passed the exam.	She studied hard, and she passed the exam.	The two independent clauses are incorrectly joined with just a comma.

Run-on Sentences

A run-on sentence occurs when two or more independent clauses are joined together without proper punctuation or conjunctions.

Incorrect	Correct	Explanation
The game was cancelled it was raining.	The game was cancelled because it was raining.	The two independent clauses are joined without any punctuation or conjunction.
He studied all night he was exhausted.	He studied all night, so he was exhausted.	The two independent clauses are joined without any punctuation or conjunction.

Misplaced Modifiers

A misplaced modifier is a phrase or clause that is incorrectly positioned in a sentence, making it unclear which word or phrase it is intended to modify.

Incorrect	Correct	Explanation
Covered in chocolate, I ate the cake.	I ate the cake covered in chocolate.	The modifier “covered in chocolate” should be closer to “cake.”
Walking down the street, the dog barked loudly.	Walking down the street, I heard the dog bark loudly.	The modifier “walking down the street” should be closer to the person walking.

Dangling Modifiers

A dangling modifier is a phrase or clause that does not clearly modify any word in the sentence.

Incorrect	Correct	Explanation
Having finished the exam, it was time to relax.	Having finished the exam, I felt it was time to relax.	The modifier “having finished the exam” does not clearly modify any word.
After cooking for hours, the dinner was finally ready.	After cooking for hours, she was glad the dinner was finally ready.	The modifier “after cooking for hours” does not clearly modify any word.

Practice Exercises

These exercises will help you practice identifying and constructing complex sentences. Each exercise focuses on a different aspect of complex sentences.

Exercise 1: Identifying Complex Sentences

Identify which of the following sentences are complex sentences. For each complex sentence, identify the independent and dependent clauses.

Sentence	Complex Sentence? (Yes/No)	Independent Clause	Dependent Clause
Because it was raining, I took an umbrella.	Yes	I took an umbrella	Because it was raining
The sun is shining.	No	N/A	N/A
After I finish my work, I will go to the gym.	Yes	I will go to the gym	After I finish my work
She likes to read books and watch movies.	No	N/A	N/A
If you study hard, you will pass the exam.	Yes	you will pass the exam	If you study hard
The book that I borrowed from the library is very interesting.	Yes	The book is very interesting.	that I borrowed from the library
He went to the store to buy some milk.	No	N/A	N/A
What he said surprised everyone.	Yes	surprised everyone	What he said
I enjoy playing the piano.	No	N/A	N/A
Although it was cold, she went for a walk.	Yes	she went for a walk	Although it was cold

Exercise 2: Combining Sentences into Complex Sentences

Combine the following pairs of simple sentences into complex sentences using the provided subordinating conjunction or relative pronoun.

Simple Sentences	Subordinating Conjunction/Relative Pronoun	Complex Sentence
It was raining. I took an umbrella.	Because	Because it was raining, I took an umbrella.
I finish my work. I will go to the gym.	After	After I finish my work, I will go to the gym.
You study hard. You will pass the exam.	If	If you study hard, you will pass the exam.
I borrowed the book from the library. It is very interesting.	That	The book that I borrowed from the library is very interesting.
It was cold. She went for a walk.	Although	Although it was cold, she went for a walk.
He arrived late. The meeting had already started.	When	When he arrived late, the meeting had already started.
She is very talented. Her paintings are famous.	Whose	The artist whose paintings are famous is very talented.
I don’t know. He wants something.	What	I don’t know what he wants.
He is a good student. He always does his homework.	Because	Because he always does his homework, he is a good student.
She practices every day. She wants to improve her skills.	So that	She practices every day so that she can improve her skills.

Exercise 3: Correcting Errors in Complex Sentences

Identify and correct the errors in the following complex sentences.

Incorrect Sentence	Correct Sentence	Explanation
Because it was raining. I stayed home.	Because it was raining, I stayed home.	The sentence was a fragment; a comma was missing after the dependent clause.
The game was cancelled, it was raining.	The game was cancelled because it was raining.	Comma splice corrected by adding subordinating conjunction.
Walking down the street, the tree was tall.	Walking down the street, I saw the tall tree.	Dangling modifier corrected by adding a subject.
After finished the exam, I felt relieved.	After finishing the exam, I felt relieved.	Corrected the incorrect verb form in the dependent clause.
Although he is tired, he continue to work.	Although he is tired, he continues to work.	Corrected the subject-verb agreement in the independent clause.
The book which I read it was very interesting.	The book which I read was very interesting.	Removed the unnecessary pronoun “it”.
She studied hard, and she passed the exam.	Because she studied hard, she passed the exam.	Improved the sentence by using a more appropriate conjunction to show cause and effect.
If I would have known, I would have told you.	If I had known, I would have told you.	Corrected the conditional clause structure.
What he said, it surprised me.	What he said surprised me.	Removed the unnecessary pronoun “it”.
The reason he was late is because he missed the bus.	The reason he was late is that he missed the bus.	Corrected the redundancy by using “that” instead of “because”.

Advanced Topics in Complex Sentences

For advanced learners, understanding more nuanced aspects of complex sentences can further enhance their writing skills. These topics include the use of elliptical clauses, reduced relative clauses, and complex sentence variations.

Elliptical Clauses

An elliptical clause is a clause in which some words have been omitted because they are understood from the context. This is common in adverbial clauses and can make sentences more concise.

• Full Clause: When I am ready, I will call you.
• Elliptical Clause: When ready, I will call you.

Reduced Relative Clauses

A reduced relative clause is a relative clause that has been shortened by omitting the relative pronoun and auxiliary verb. This is common when the relative clause uses a present participle or past participle.

• Full Clause: The book that is lying on the table is mine.
• Reduced Clause: The book lying on the table is mine.

Complex Sentence Variations

Complex sentences can be combined with other sentence structures to create more complex and sophisticated writing. This includes using compound-complex sentences (sentences with multiple independent clauses and at least one dependent clause) and embedding multiple dependent clauses within a single sentence.

Example of a Compound-Complex Sentence: Because it was raining, the game was cancelled, and everyone went home.

Frequently Asked Questions (FAQ)

This section addresses common questions about complex sentences.

1. What is the difference between a simple sentence and a complex sentence?

   A simple sentence consists of only one independent clause, expressing a complete thought with a subject and a verb. A complex sentence, on the other hand, contains one independent clause and at least one dependent clause, which adds additional information or context to the main idea.

2. How can I identify the independent and dependent clauses in a complex sentence?

   An independent clause can stand alone as a sentence because it expresses a complete thought. A dependent clause cannot stand alone and is usually introduced by a subordinating conjunction or a relative pronoun. Look for these conjunctions and pronouns to identify the dependent clause.

3. Do I always need a comma when the dependent clause comes first in a complex sentence?

   Yes, generally, a comma is required after the dependent clause when it comes before the independent clause. This helps to separate the clauses and improve readability.

4. Can a complex sentence have more than one dependent clause?

   Yes, a complex sentence can have multiple dependent clauses. These clauses can be of the same type (e.g., multiple adverbial clauses) or different types (e.g., one adverbial clause and one adjective clause).

5. What are some common subordinating conjunctions?

   Some common subordinating conjunctions include: after, although, as, because, before, even if, even though, if, since, so that, than, though, unless, until, when, where, and while.

6. What are some common relative pronouns?

   Common relative pronouns include: who, whom, which, that, and whose.

7. How can I avoid comma splices when writing complex sentences?

   To avoid comma splices, make sure that you do not join two independent clauses with only a comma. You can correct a comma splice by adding a coordinating conjunction (e.g., and, but, or), using a semicolon, or separating the clauses into two separate sentences.

8. What is a misplaced modifier, and how can I avoid it?

   A misplaced modifier is a phrase or clause that is incorrectly positioned in a sentence, making it unclear which word or phrase it is intended to modify. To avoid misplaced modifiers, make sure that the modifier is placed as close as possible to the word or phrase it is intended to modify.

9. How do I make sure my pronouns have clear references in complex sentences?

   Ensure that each pronoun clearly refers to a specific noun or pronoun in the sentence or previous sentences. Avoid using pronouns that could refer to multiple nouns or pronouns, as this can create confusion.

10. Are complex sentences always better than simple sentences?

    Not necessarily. While complex sentences can add nuance and detail to your writing, it’s important to use them appropriately. Overusing complex sentences can make your writing difficult to read and understand. A good balance of simple, compound, and complex sentences is often the most effective approach. The best sentences are clear, concise, and convey the intended meaning effectively.

Conclusion

Mastering complex sentences is essential for effective communication in English. By understanding their structure, types, and usage rules, you can enhance your writing and speaking skills, express nuanced ideas, and create more engaging and persuasive content.

This article has provided a comprehensive guide to complex sentences, covering everything from basic definitions to advanced topics. Remember to practice regularly, pay attention to punctuation and grammar, and strive for clarity in your writing.

Continue to explore different types of sentences and grammar concepts to further improve your language proficiency. With consistent effort and attention to detail, you can become a confident and skilled communicator.

Remember that the journey to mastering English grammar is ongoing, and each new concept you learn brings you closer to fluency and precision in your language skills.