Complex Sentence

A complex sentence contains an independent clause and at least one dependent clause. An independent clause can stand alone as a sentence and makes a complete thought and a dependent clause can not stand alone, even though it has a subject and a verb.

Introducing complex sentence structures in America 

Complex sentences are basic sentence forms found in American English grammar structure. These sentences string together a complete and incomplete thought.

Or, in other words, a complex sentence has one independent clause (a sentence that is complete) and at least one dependent clause (a sentence that is incomplete, such as prepositional phrases). An independent clause (unlike a dependent clause) can stand alone as a sentence.

Learning the difference between complex and compound sentence structures is typically taught during the freshman year in high school. However some students either learn these structures in junior high or middle school, or during their freshman year in college during remedial coursework.

Complex sentence and proper usage 

Complex sentences have one independent clause and a dependent clause, separated by a comma. There are a few instances where a comma is not necessary. Here are a few examples of complex sentences with the independent clause underlined.

• Stay in the bath until the phone rings.
• The car swerved to miss Mrs. Jackson, who had slipped off the pavement.
• Both the cockroach and the bird would get along very well without us, although the cockroach would miss us most.
• Leave while you can. (Declarative sentences sometimes only have one word in the independent clause because the subject is assumed.)
• When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.

While complex sentences do require an independent and dependent clause, they can have more than one dependent clause, but not more than one independent clause. If a sentence has more than one independent clause, it is referred to as a compound sentence.

Complex sentences - Representing one of four main structures 

Complex sentences are one of the four main sentence structures found in American Standard English and other forms of English. The four types of sentences include compound-complex sentences, simple sentences, complex sentences, and compound sentences.

The most common type of sentence is the simple sentence. This is because it requires less information, is shorter, and may be easier to understand. Compound sentences are the next most common sentence structure because the rules are a little more simplistic than complex and compound-complex sentences. 

The most common compound sentence structure utilizes propositional phrases. For example, “Once upon a time, Cinderella lived with her two evil stepsisters and stepmother” has a prepositional phrase leading into the independent clause.

Here are examples of the four types of sentences:

Complex Sentence: an independent clause and at least one dependent clause

“The human brain never stops working until you stand up to speak in public.”

Compound Sentence: at least two independent clauses

“I always wanted to be somebody, but I should have been more specific.”

Simple Sentence: one independent clause

“Curiosity killed the cat.”

Compound-Complex Sentence: has at least two independent clauses and at least one dependent clause

“I stopped believing in Santa Claus when my mother took me to see him in a department store, and he asked for my autograph.”