Complex Sentence

We all know what sentences are, but do you know the different types of sentence structures and how to form them? There are four different types of sentences in English; simple sentences, compound sentences, complex sentences, and compound-complex sentences. This explanation is all about complex sentences.

Keep reading to find out more, if you like. (p.s that's a complex sentence!)

Complex sentence meaning

Complex sentences are longer sentences consisting of one independent clause and one or more dependent clauses. They are one of only two sentence types to include a dependent clause.

Clauses are the building blocks of sentences, and every clause must contain a subject and a verb. There are two types of clauses; independent clauses and dependent clauses.

An independent clause does not rely on any other clause to make sense; it is 'independent' and works on its own. On the other hand, a dependent (or subordinate) clause is 'dependent' on the independent clause to make sense. Dependent clauses add additional information to an existing sentence and cannot stand alone.

Fig 1. Complex sentences often occur in most communications.

Complex sentence structure

A complex sentence contains one independent clause and one or more dependent clauses joined together with subordinating conjunctions, relative pronouns, and punctuation.

The independent clause can come at the beginning, in the middle, or even at the end of the sentence. Because of this, there is not a set formula for a complex sentence.

We form complex sentences by centring the sentence around the independent clause (the main clause) and using dependent clauses to add additional information that expands on the main clause.

Dependent and independent clauses in complex sentences

Being able to correctly identify dependent and independent clauses is crucial when forming complex sentences. Although both clauses contain a subject and a verb, there is a difference between the two.

• Independent clauses can stand alone as a complete thought.

• Dependent clauses rely on the independent clause to complete the thought.

Another way we can identify dependent clauses is the use of subordinating clauses. As a general rule, dependent clauses will begin with a subordinating clause. Let's look into this a little more...

Subordinating conjunctions in complex sentences

A subordinating clause is a linking word used to join a dependent clause to an independent clause. They are similar but differ from coordinating conjunctions, which join two independent clauses together.

Here is a list of subordinating conjunctions you can use to join a dependent and an independent clause;

• if

• because

• since

• until

• although

• even though

• while

• before

• after

• once

• as

• as if

• so that

• only if

Relative pronouns are a type of subordinating conjunction used to join clauses. Here is a list of the relative pronouns you can use;

• when
• who
• whoever
• whom
• whomever
• whose
• whatever
• which
• whichever

Commas in compound sentences

Although complex sentences sound pretty 'complex', the only thing you have to worry about is choosing the correct subordinating conjunction and using a comma. But where does the comma go? I hear you ask. The position of the comma depends on the order of the clauses.

• When the dependent clause comes first, place the comma just after and before the independent clause. E.g. 'When I'm feeling sleepy, I like to watch Freinds on Netflix.'

• When the independent clause comes first, there is no need to use a comma. E.g. I like to watch Freinds on Netflix when I'm feeling sleepy.'

Let’s look at some more examples of complex sentences.

Complex sentence examples

Here are some examples of complex sentences. The independent clause is in bold, and the link is in purple.

Let’s explore one of these examples in a little more detail so that you can get to grips with how complex sentences work:

Here we can see that the dependent clause 'when she was younger' begins with the subordinating conjunction 'when'. It is a dependent clause because it contains a subject (she) and a verb (was) but does not make sense on its own. The independent clause 'she believed in Santa' is needed to complete the thought.

Fig 2. She believed in Santa when she was young

When to use complex sentences

Complex sentences are often used in spoken and written English because they give more information in a concise way. As complex sentences can include multiple dependent clauses, they can contain a lot of information.

In this sentence, the dependent clause adds more information to the independent clause 'he returned the parcel' by giving us the reason why the man is returning the parcel.

How to identify a complex sentence

Whenever we try to identify a particular type of sentence, we should look at the number and type of clauses the sentence contains.

In complex sentences, we are looking out for at least two clauses: one independent clause and one or more dependent clauses.

Complex sentences are similar to compound sentences, as well as compound-complex sentences, but they are not the same. Let’s take a look at their differences.

• Compound sentences don't have dependent clauses. So, if you can see a dependent clause in a sentence, it is either a complex or compound-complex sentence.

• Compound-complex sentences are often the longest sentence type. They include at least two independent clauses and at least one dependent clause. If there is only one independent clause and one or more dependent clauses then it's a complex sentence.

So, if there’s one independent clause and at least one dependent clause, you can be sure it’s a complex sentence!