Complex Sentence

A complex sentence is made up of an independent clause and one or more dependent clauses connected to it. A dependent clause is similar to an independent clause, or complete sentence, but it lacks one of the elements that would make it a complete sentence.
Examples of dependent clauses include the following:

• because Mary and Samantha arrived at the bus station before noon
• while he waited at the train station
• after they left on the bus

Dependent clauses such as those above cannot stand alone as a sentence, but they can be added to an independent clause to form a complex sentence.
Dependent clauses begin with subordinating conjunctions. Below are some of the most common subordinating conjunctions:

• after
• although
• as
• because
• before
• even though
• if
• since
• though
• unless
• until
• when
• whenever
• whereas
• wherever
• while

A complex sentence joins an independent clause with one or more dependent clauses.

A complex sentence joins an independent clause with one or more dependent clauses.
The dependent clauses can go first in the sentence, followed by the independent clause, as in the following:

1. Because Mary and Samantha arrived at the bus station before noon, I did not see them at the station.
2. While he waited at the train station, Joe realized that the train was late.
3. After they left on the bus, Mary and Samantha realized that Joe was waiting at the train station.

Conversely, the independent clauses can go first in the sentence, followed by the dependent clause, as in the following:

1. I did not see them at the station because Mary and Samantha arrived at the bus station before noon.
2. Joe realized that the train was late while he waited at the train station.
3. Mary and Samantha realized that Joe was waiting at the train station after they left on the bus.

Complex sentences are often more effective than compound sentences because a complex sentence indicates clearer and more specific relationships between the main parts of the sentence. The word "before," for instance, tells readers that one thing occurs before another. A word such as "although" conveys a more complex relationship than a word such as "and" conveys.