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Complex Sentence Structure

Hedieh Najafi, Bethany Calderwood, Linsey Betts
  • Author
    Hedieh Najafi

    Hedi Najafi earned her Ph.D. in Educational Leadership and Policy Studies from Arizona State University. She also has an M.A. and B.A. in English Language and Literature. In addition, she has several certificates and certifications such as Tesol Ontario, Laubach Literacy of Canada Tutor Certificate, and Financial Markets from Yale. In addition to teaching in North America, Dr. Hedi Najafi has taught in many institutions of higher education around the world. She has been teaching ESL, English, General Education, and Educational Leadership courses for the past twenty years.

  • Instructor
    Bethany Calderwood

    Bethany is a certified Special Education and Elementary teacher with 11 years experience teaching Special Education from grades PK through 5. She has a Bachelor's degree in Special Education, Elementary Education, and English from Gordon College and a Master's degree in Special Education from Salem State University.

  • Expert Contributor
    Linsey Betts

    Linsey is currently pursuing her Ph.D. in English Literature at Claremont Graduate University and has taught students of all ages in English and the humanities for 10 years.

Learn what makes a complex sentence and study the complex sentence structure. Explore the different types of clauses and see examples of writing complex sentences. Updated: 12/02/2021

Table of Contents


Complex Sentence Structure

A verb is the action in a sentence. A subject is a noun or pronoun that either performs or receives the action of the sentence. A complex sentence is a sentence that contains an independent clause and at least one dependent clause.

A clause is a group of words that contains a subject and a verb. If a clause conveys a complete meaning, it is an independent clause i.e., a complete sentence. An independent clause can stand alone. In contrast, a dependent clause does not make sense by itself. A dependent clause, also known as a subordinate clause, is a clause that starts with a subordinating conjunction. A dependent clause has a subject and a verb but does not convey a complete thought.

There are many different subordinating conjunctions in the English language. The following table lists some of the more commonly used subordinating conjunctions.

although because since
than whereas though
unless if where
wherever after before
by the time when until
even even though while

What makes a complex sentence? In line with the complex sentence structure, complex sentences form when an independent clause is added to a subordinate clause, using a subordinating conjunction.

  • Susana went to medical school after she got her B.S.

In the example above, after is the subordinating conjunction. The independent clause Susana went to medical school is connected to the dependent clause after she got her B.S.

Simple, Compound, & Complex-Compound Sentences

Having a variety of sentence types makes written work more effective, easier to read and understand, and more interesting. There are different kinds of sentences that writers can employ in their writings. For example, in addition to complex sentences, there are simple, compound, and complex-compound sentences in the English language.

A simple sentence is a sentence that contains one subject, one verb, and a complete thought. A simple sentence is, in fact, an independent clause.

  • Canada has ten provinces.

In this example, Canada is the subject, and has is the verb. The thought of the sentence is complete.

An example of a simple sentence: Canada has ten provinces.

Simple sentence

A compound sentence is a sentence that contains two independent clauses connected to each other by a coordinating conjunction. The coordinating conjunction must be preceded by a comma. There are seven coordinating conjunctions in the English language:

  • for
  • and
  • nor
  • but
  • or
  • yet
  • so

Canada has ten provinces, and it has three territories as well. This sentence is a compound sentence because two independent clauses, Canada has ten provinces and it has three territories as well, are connected to each other by the coordinating conjunction and preceded by a comma. Canada and it are subjects, and has is the verb in both independent clauses.

A complex-compound sentence contains a compound sentence (two independent clauses connected by a coordinating conjunction) and a dependent clause.

  • Hossein's B.S. is in chemical engineering, and his M.S. is in chemistry whereas his Ph.D. is in education.

This is an example of a complex-compound sentence. This sentence is made up of two independent clauses (simple sentence) and a dependent clause. Hossein's B.S. is in chemical engineering and his M.S. is in chemistry are two independent clauses connected to each other by the coordinating conjunction and. Whereas is a subordinating conjunction. It connects the dependent clause whereas his Ph.D. is in education to a compound sentence, creating a complex-compound sentence.

Hossein's B.S. is in chemical engineering. Simple sentence / independent clause
and Coordinating conjunction
His M.S. is in chemistry. Simple sentence / Independent clause
whereas his Ph.D. is in education Subordinating conjunction and dependent clause

While a simple sentence has one independent clause, and a compound sentence has two independent clauses, a complex sentence has an independent and a dependent clause. A complex-compound sentence, on the other hand, contains two independent clauses and one dependent clause.

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How to Write Complex Sentences

Writers often wonder how to write complex sentences. Writing complex sentences is not a difficult task if writers bear in mind what makes a complex sentence: an independent and a dependent clause, with the dependent clause starting with a subordinating conjunction.

How do you create a complex sentence? The first step in writing a complex sentence is to recognize the dependent and independent clauses. Then the clauses must be written in one sentence. If the complex sentence starts with the dependent clause, it must be separated from the independent clause by a comma. If the complex sentence starts with the independent clause, no comma is necessary.

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Editing Practice

Creating a good piece of writing is like creating a work of art. It takes hard work, skill, and practice. In this lesson, we discussed how creating complex sentences can improve the quality of your writing my making it flow better. Try editing the paragraph below (a sample of someone writing for a cooking blog) using complex sentences to make the writing sound better and more smooth.
Remember: complex sentences have one independent clause (complete thought) and at least one subordinate clause (or incomplete thought)!

Editing Exercise

This is a recipe for homemade chocolate chip cookies. It is my grandmother's recipe. She always brought these to family dinners. Everyone loved them. The first step is preheat the oven to 350°. This saves time. The oven can heat while you prepare the dough. Mix one cup of soft butter with one cup of white sugar. Mix them until they are soft. Then add one cup of packed brown sugar. Add two eggs. Only add them one at a time. Pour in the vanilla extract (two teaspoons). Then mix one teaspoon of baking soda in two teaspoons of hot water and wait for it to dissolve then add it to the bowl. Then add half a teaspoon of salt. Then put in three cups of flour. Next is two cups of semisweet chocolate chips. Then add one cup of chopped walnuts. You can use another kind of nut if you want. Or you can leave out the nuts. Drop the batter from a spoon onto an ungreased cookie sheet. Bake the cookies for ten minutes. We always remember my grandmother when we eat these.

Sample Edit

This is my favorite recipe for homemade chocolate chip cookies, straight from my grandmother's kitchen. These cookies were my favorite part of family dinners as a child (and my family's favorite part too). The very first step in this recipe is to preheat your oven to 350°, which saves time by letting your oven heat up as you prepare the dough. Next, mix a cup of softened butter, one cup of white sugar, and one cup of packed brown sugar until the mixture is nice and soft. Then, add two eggs, one at a time, and two teaspoons of vanilla extract. The next step is to dissolve one teaspoon of baking soda in two teaspoons of hot water. Add that to the mixture along with half a teaspoon of salt, three cups of flour, and two cups of semisweet chocolate chips. If you and your family like nuts in your cookies, then add one cup of chopped nuts, which is an optional ingredient in this recipe. Granny always used walnuts. Using a spoon, drop spoonfuls of the batter onto ungreased cookie sheets and bake them for ten minutes. Tasting these cookies fresh out of the oven always makes me remember my grandmother!

What is an example of a complex sentence?

The following is an example of a complex sentence.

Ex: You will feel comfortable writing complex sentences, after you go through this lesson.

How do you identify complex sentences?

The most obvious marker of a complex sentence is its subordinating conjunction. Therefore, if a sentence contains a subordinating conjunction and at least one dependent clause and one independent clause, that sentence can be identified as a complex sentence.

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