4 Types of Sentences You Need To Know

There are four types of sentence in English: simple, compound, complex, and compound-complex. In this article, we will learn how to form each of them. First, however, we must look at clauses.

There are essentially two kinds of clauses: independent and dependent.

a) Independent Clauses

An independent clause must have three elements:

A subject
A verb
A complete thought

It is relatively easy to understand those first two, but how do you know whether or not a clause contains a complete thought? In fact, that is not so difficult. If it contains a complete thought, the sentence alone can be completely understood. In other words, no extra information is necessary.

Let’s look at some examples:

Sally sings.
She loves you.
We are going to the mall this weekend.

In the first example, there are only two words! This is a little unusual, but it goes to show that an independent clause can consist of nothing more than the subject and verb, and yet contain a complete thought. Nothing else is needed. If I told you, “Sally sings,” you may have extra questions, but you get my meaning.

b) Dependent Clauses

On the other hand, dependent clauses do not contain a complete thought. This is because they almost always begin with a subordinator. A subordinator makes this clause less important to the meaning of the whole sentence, and therefore it must be attached to an independent clause to be fully understood. “Subordinate” means “less important” and some people call these subordinate clauses for that reason.

Take a look at this clause:

because he wanted to find out the answer.

Here, “because” is a subordinator. Alone, this could not function as a sentence. It would be called a sentence fragment, meaning that it is only part of an idea. Instead, we need to add it to an independent clause:

Allen went to the teacher’s office because he wanted to find out the answer.

If I told you, “Allen went to the teacher’s office,” you would be able to understand me. It is a completely self-contained idea, and therefore it is able to function as a sentence. However, it is possible to add more information. In this case, we have added a dependent clause. The dependent clause could not function alone because if I said to you “because he wanted to find out an answer,” you simply could not understand my whole meaning.

Here are some common subordinators:

After
Though
Although
Unless
Because
What
Before
When
Even though
Where
If
Which
Since
While
That
Who

1. Simple Sentences

A simple sentence is just one independent clause by itself. It may have one subject and one verb, or several subjects and several verbs.

Rain falls from the sky.
Susie and Karen play basketball on weekends.
I like eating fast food.
She went to the park yesterday.
They were last seen six days ago.

2. Compound Sentences

A compound sentence is made up of two (or more) independent clauses. They may be joined by:

a comma and a coordinating conjunction (FANBOYS*)
- I like tea, but I prefer coffee.
a semi-colon
- I like tea; I prefer coffee.
a semi-colon and a conjunctive adverb.
- I like tea; however, I prefer coffee.

3. Complex Sentences

A complex sentence has one independent clause and at least one dependent clause.

The two clauses will be joined by a subordinator (although, because, since, as) or relative pronoun (who, which, that).

Although it was raining, I walked to work.

In this example, “although” is the subordinator and thus “Although it was raining” is a dependent clause.

In a complex sentence, you can put the dependent clause first or second. It really doesn’t matter; however, you should be careful with the punctuation. If the dependent clause goes first in a sentence, it should be followed by a comma. If the independent clause comes first, no comma is needed:

Although it was raining, I walked to work.
I walked to work although it was raining.

The formula looks like this:

Independent clause + dependent clause

Dependent clause + comma + independent clause

= complex sentence

You can drop the dependent clause, but you cannot drop the independent one

I walked to work. (CORRECT)
Although it was raining. (WRONG)

The first example is now a simple sentence, but the second is a sentence fragment. Any single clause beginning with a subordinator is a fragment. This is a big mistake, and you should try to avoid it in your IELTS writing. Subordinate clause is another way of saying dependent clause. Subordinate means that a clause is less important than the main clause.

Look at these two simple sentences:

I was tired. I went to the shop.

Now look at this compound sentence:

I was tired but I went to the shop.

In each case, the sentences have equal meaning. They are equally important. In a complex sentence, however, one clause is more important and one is less important.

Although I was tired, I went to the shop.

Now the reader knows which part of the sentence is the main idea – “I went to the shop.”

4. Compound-Complex Sentences

As the name suggests, this type of sentence is a mix of compound and complex sentences. It must have at least two independent clauses, and one dependent clause, meaning it has at least three clauses. We use the same conjunctions (subordinators or FANBOYS) to join the different parts; however, the clauses could go in any order.

The dog barked loudly, and she ran all around the room as her owner tried to relax with his newspaper.
The scouts did not think they’d make it to the destination because it was so far away, and they were exhausted from the long journey.

Note the conjunctions above. They are used just the same as in complex or compound sentences.

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