Types of Sentences According to Structure (Simple, Complex, Compound & Complex-Compound)

Types of Sentences According to Structure! The function and clause structure also determine the classification of sentences. Based on the clause structure in which they are arranged and the function they do, sentences are classified into four types.
  1. Simple Sentence
  2. Complex Sentence
  3. Compound Sentence
  4. Compound-Complex Sentence

Types of Sentences According to Structure (Simple, Complex, Compound & Complex-Compound)

Types of Sentences According to Structure: What is a Simple Sentence? 

A sentence that consists of one finite verb and expresses a single complete and independent thought is called a simple sentence. A simple sentence must have one clause, whether it is short or long, and does not have any coordination or subordination.

How to Make a Simple Sentence?

All simple sentences can be split into two parts the subject and the predicate. The subject of a simple sentence consists of an adjective or a noun phrase, and the predicate consists of a finite verb. The meaning of the simple sentence can be enhanced by adding adjectives or adjective phrases, adverbs, or adverbs phrases.

Examples of Simple Sentences
  • She loved her son.
  • Everything is going fine.
  • Nothing happened.
  • Her son fell sick.
  • Come. (The subject is you in this sentence which is understood)
  • Time flies.
  • I don’t believe them.
  • Going home, she stopped by the fruit shop to buy some bananas and some apples.
  • Ahmad and his sister played music and watched TV.
  • He looks after his minor brother.
  • The dogs barked.


Some sentences begin with conjunction and consist of one clause; such sentence is still called a simple sentence.


  • He says he loves her. But we don’t believe him.
  • All the students will have to work hard if they are going to pass their exams. And they must start right away.
  • She cooked the food. Furthermore, she served dinner.

Types of Sentences According to Structure: What is a Complex Sentence? 

A sentence made of at least two clauses, one is the main or independent, and one or more is dependent or subordinate, is called a complex sentence. The subordinate clause or clauses in a complex sentence are linked to the main clause by subordinating conjunction. If, until, because, when, even though, unless, even if, whether, until, etc., are subordinating conjunction. 

Each clause in a complex sentence, whether it’s independent or dependent, has its own subject and verb.
A clause is a smaller sentence made of a subject and a finite form of a verb that is linked to form a larger sentence. A clause can be structured in the same way as a sentence but which is a part of a larger sentence or a sentence within a sentence. Clauses are divided into two classes.

Main or Independent Clause

A clause that could exist as a separate sentence is called an independent clause. It contains its own subject and a verb and can stand by itself. 

Subordinate or Dependent Clause

A clause that depends on another clause and cannot form a separate sentence is called a subordinate clause. A subordinate clause that makes a part of a complex sentence can be either a noun clause, an adjective, or an adverb clause
An independent clause can form a sentence when joined by conjunction with the main clause.
Study the following examples.

whenever she goes to school
when she is absent
whom I met at the shopping mall 
We can see that these clauses can’t stand by themselves, i.e., they cannot convey the whole idea. In this case, an independent clause needs to be linked to these dependent clauses to make complete sense.

Whenever she goes to school, she meets her parents.

The class looks pretty empty when she is absent.

I had a great discussion with a boy whom I met at the shopping mall

Examples of Complex Sentences 

  • In each sentence below, the parts written in bold are dependent clauses.
  • We will start studying when he comes home.
  • I did it because I love you.
  • He was only fifteen when his mother died.
  • I will never tell him the problem unless he agrees to help.
  • When she got home from school yesterday, she played the guitar for two hours.
  • Students spend a lot of time playing video games even though they know it’s a waste of time.
  • Unless you register, you won’t access the complete study materials.
  • I watched TV while my roommate was sleeping.
  • Even if she doesn’t prepare well, she is going to pass the exam.
  • Ahmad was only five when he was admitted to school, although he looked much older.
Note: In complex sentences, the order of the clauses doesn’t matter. When we place the dependent clause, first a comma should be placed after it, then an independent clause. But if the independent clause comes first, we don’t put a comma after it.

Types of Sentences According to Structure: What is a Compound Sentence?

A sentence consists of at least two or more independent clauses that are joined by coordinating conjunction is known as a compound sentence. Each sentence or clause in a compound sentence has its own subject and predicate but which is a part of a large sentence. The clauses which make a compound sentence are called co-ordinate clauses.
Common coordinating conjunctions used in a compound sentence to link clauses together are and, but, and or. The four coordinating conjunctions yet, for, so, and nor are less commonly used.

How to make a compound sentence? 

Since a compound sentence contains two simple sentences, let’s take examples of how we can join two or more simple sentences to make a single compound sentence.
Simple Sentence-1: He can go now.
Simple Sentence-2: He can go later.
Here in this example, we have two simple sentences, but it sounds disconnected if we say it like that. We can combine them by substituting suitable coordinating conjunction to make one compound sentence. The first clause in a compound sentence should be followed by a comma, coordination conjunction, and then the second clause. This is the proper form of a compound sentence.


Compound Sentence: He can go now, or he can go later.
Simple Sentence-1: I am a teacher.
Simple Sentence-2: My brother is a doctor.
Compound sentence: I am a teacher, and my brother is a doctor.
Simple Sentence-1: Ahmad tried to complete the assignment.
Simple Sentence-2: The assignment was too lengthy.

Compound Sentence: Ahmad tried to complete the assignment, but it was too lengthy.
Independent Clause-1: They are eating their dinner at his house tonight.
Independent Clause-2: His brother is going to the cafeteria.
Compound Sentence: They are eating their dinner at his house tonight, but his brother is going to the cafeteria.
Note: Clause is another name used for a simple sentence.

Further Examples of Compound Sentences 


  • She doesn’t feel well, so she doesn’t want to go with us.
  • I want to meet my friend’s parents, but I don’t have free time right now.
  • He told his sister to turn off the light, but she didn’t, so he left the room.
  • I have completed the post, but I cannot publish it yet.
  • I watch the news in the morning, and my children play cricket, but my baby sleeps.
  • The woman is old; still, she is strong.
  • I’m out of money, so I’ve come to the bank for a loan.
Sometimes the coordinate clauses in a compound sentence may not be connected by a coordinating conjunction. In this case, each clause is just followed by a comma.


  • I looked at the baby, scratched his head, and he cried.
  • I came home late last night, ate the meal, and went straight to bed.

When to Form a Compound Sentence?

To form a compound sentence, each coordinate clause should be closely related and should be of equal rank. We have to keep the following three points in mind when we want to make a compound sentence.
  1. Each coordinate clause must contain a subject and a verb of its own.
  2. Each clause should express the complete idea.
  3. All the clauses should be closely related and should be of equal rank.
If all these three conditions are met, we can then form one compound sentence of two or more coordinate clauses.
The horse reared. I will not do it at all.


In this example, both the clause contains the subject and verb of its own. The underlined part is the subject, and the part written in bold is the verb.


Both the clauses express the complete thought.
But the third condition isn’t met. Both the clauses aren’t closely related, i.e., have nothing to do with each other. So, we can’t join them to make one compound sentence.
They burned animal fat for light. The animal fat smelled horrible.  


In this example, the underlined part expresses the subject, and the part written in bold is the verb. Both the clauses have their own subject and verb. 
Each clause can stand alone to express a complete idea.
Both clauses are of equal importance and closely related.
Since all the three conditions are met so we can combine them to make one compound sentence.
Compound Sentence: They burned animal fat for light, but it didn’t smell very pleasant.  

Types of Sentences According to Structure: What is a Complex-Compound Sentence? 

A sentence made of one or more main(also known as independent clauses) and one or more dependent or subordinate clauses is called a complex-compound sentence.
Complex-Compound Sentence Examples 
  • Come if you can, and I’ll teach in my home.
  • We first met here when I was thirteen, and I meet him here every year since then.
  • Because I love to watch movies, I like to read books, and I enjoy going out with friends too.
  • I went to buy a gift for her after class was over; however, the shopping mall was already closed.

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