A group of words or phrases that includes a subject and a verb. A clause is usually only part of a sentence and works as a syntactic constituent.
Types of Clauses
Principal Clauses
Subordinate Clauses
Coordinate Clauses

Principal clauses (or Independent clauses or Root clauses or Matrix.)
The principal clause is well formed to express its meaning. A principal clause can work as a simple sentence. A principal clause has a subject and a finite verb. It may have one or more than one non- finite verbs.
Example:
I go to school and I read books.
He is a good student. ( Here it is a complete sentence)
He is my brother who thinks of himself as a celebrity.

Coordinate clauses
When two or more principal clauses are joined by coordinating conjunctions, they are called coordinate clauses. Coordinate clause can also join two constituents of equal value, for example word with word, phrase with phrase, and clause with clause.
Coordinators: For (effect/cause), And (addition), Nor (addition of negatives), But (contrast), Or (alternative), Yet (contrast), So (cause/effect).
Examples:
You may do it now or you may get out.
I like meat and I like rice.
Some men are bad but some men are good.

Subordinate clauses
Subordinate clauses are not complete in themselves. They depend on a principal clause. A subordinate clause therefore can not be used as a complete sentence without the help of a principal or root clause. for their dependency we named them subordinate to main clause.
Subordinators/Subordinating Conjunctions
Although, even though, though, whereas, while (contrast)
Since, Because (cause/effect), When(time), If (condition)

Embedding or Nesting
Embedding is the process by which one clause is included or embedded in another. Broadly, embedding is the inclusion of any linguistic unit or constituent as part of another unit of the same general type. Subordination is a major type of embedding in English grammar.

Subordinate clauses
Noun Clauses
A noun clause is used in a sentence in the same way as a noun is used as:
Subject
Object
Object of preposition
Complement
Examples:
That he is honest is known to me.
I know that he is honest.
The patient is worried about what the doctor has said.
Our hope is that he will come back soon.

Adjective clause or Relative clause
An adjective clause or relative clause is used as an adjective that denotes relation with the antecedent. An adjective clause is a dependent clause that often begins with words such as: that, when, where, who, whom, whose, which or why .
Adjective clause may be
Essential and
Inessential

Essential adjective clauses
Essential adjective clauses can not be removed from the sentence as they form more required meaning as a constituent.
Examples:
The music class that Shyam takes focuses on lyrics.
Mr. Dhupia is the teacher who helped me with grammatical fundamentals.

Inessential adjective clauses
An Inessential adjective clause provides additional information about the word it modifies, but the meaning of the sentence is already clear .
Inessential adjective clause is always set off with commas .
Examples:
The house on the right, which belongs to Raj , is up for sale .
Raj, who is honest, just got back from a trip to Mumbai.

Adverbial clauses
An adverbial clause usually expresses: time , place, cause, reason, effect, result, manner, condition, comparison, contrast, purpose.
In simple words an adverbial clause does the same work of an adverb in a sentence, that to qualify the verb, adjective or an adverb.
Examples:
Father came when I started for Mumbai.
You may go where you like.
Raj will not come because he is ill.

Let us study clauses in relation to sentences:
Sentences may be classified into three types according to their grammatical structure:
1. Simple sentences, 2. Compound sentences, 3. Complex sentences.

A simple sentence has only one clause i.e. one subject and one predicate but it has a complete meaning, e.g.
The students are playing cricket.
A compound sentence has two or more main clauses joined together by coordinating conjunctions like and, but, so, and so, therefore, for, yet, still, now, or, otherwise, either…………… or, neither……… nor, not only……… but also, e.g.
She ran fast and caught the bus.
Ankit worked hard but failed to qualify.
A complex sentence has one main clause and one or more subordinate clauses, e.g.,
He said that truth wins in the end.
I know the lady who wrote this novel.
Let us wait till she arrives.

Exercises
A. Answer the following questions.
1. What is a clause ? How is it different from a phrase ?
2. What are the types of clauses ?
3. What is principal clause ?
4. Why would a clause be called a subordinate clause?
5. What do you mean by embedding in English grammar?
6. Write the two main types of conjunctions.
7. What is an essential adjective clause ? and how it is different from an inessential adjective clause?
8. What is the work of a coordinator ?

B. State whether the subordinate clause used in the following sentences is an adjective clause, adverb clause or noun clause.
1. My friend helped me when I was in danger.
a. Adjective clause
b. Adverb clause
c. Noun clause

2. We believe in democracy though it has its shortcomings.
a. Adjective clause
b. Adverb clause
c. Noun clause

3. My parents were happy because I won the first prize.
a. Adjective clause
b. Adverb clause
c. Noun clause

4. This is the girl who talked to me yesterday.
a. Adjective clause
b. Adverb clause
c. Noun clause

5. I have lost the tickets which I bought.
a. Adjective clause
b. Adverb clause
c. Noun clause

6. He could not answer any of the questions that I asked him.
a. Adjective clause
b. Adverb clause
c. Noun clause

7. Although he is very rich, he is a miser.
a. Adjective clause
b. Adverb clause
c. Noun clause

8. Everybody admits that he is a brave man.
a. Adjective clause
b. Adverb clause
c. Noun clause

9. We knew that he was guilty.
a. Adjective clause
b. Adverb clause
c. Noun clause

10. What he told me was a lie.
a. Adjective clause
b. Adverb clause
c. Noun clause

11. He gave me everything that I asked for.
a. Adjective clause
b. Adverb clause
c. Noun clause

12. Your statement that you lost the money cannot be believed.
a. Adjective clause
b. Adverb clause
c. Noun clause

13. The jury believed that the man was guilty.
a. Adjective clause
b. Noun clause
c. Adverb clause

14. Come when you like.
a. Noun clause
b. Adjective clause
c. Adverb clause

15. I know the girl who won the prize.
a. Noun clause
b. Adjective clause
c. Adverb clause

16. He confessed that he was guilty.
a. Noun clause
b. Adjective clause
c. Adverb clause

17. I know you have great regard for him.
a. Noun clause
b. Adjective clause
c. Adverb clause

18. Do you think that I am a fool?
a. Noun clause
b. Adjective clause
c. Adverb clause

19. Before I die I want to see Venice.
a. Noun clause
b. Adjective clause
c. Adverb clause

20. The hand that rocks the cradle rules the world.
a.Noun clause
b. Adjective clause
c. Adverb clause

21. I know a boy whose father serves in the army.
a. Noun clause
b. Adjective clause
c. Adverb clause

22. I will not go until he arrives.
a. Noun clause
b. Adjective clause
c. Adverb clause

23. The coffee maker that I bought for my wife is expensive.
a. Noun clause
b. Adjective clause
c. Adverb clause

24. If you give respect, you get respect.
a. Noun clause
b. Adjective clause
c. Adverb clause

C. Clauses are in capital letter, identify whether they are dependent or independent.
1. If you don’t fix the car, IT WILL CONTINUE TO LEAK OIL.
2. WHILE THE CAR IS BEING FIXED, we will need to take the bus.
3. It isn’t necessary to cram all night IF YOU HAVE STUDIED A LITTLE EACH DAY.
4. Before you begin studying for the exam, YOU WILL PROBABLY WANT TO REST.
5. I can’t go to the movies SINCE I DON’T HAVE ANY MONEY.
6. WHETHER HE ATTENDS THE PARTY OR NOT, I have decided to go.
7. I WILL STOP PLAYING THE DRUMS when you go to sleep.
8. SINCE YOU’VE TAKEN YOUR EXAM IN BIOLOGY, you probably don’t feel like studying for tomorrow’s exam in math.
9. Until he apologizes to me for his rude behavior, I REFUSE TO SEE HIM.
10. I wore my boots BECAUSE IT LOOKED LIKE IT MIGHT SNOW.
11. I WILL GO ON A TRIP if the car is in good working order.
12. SINCE THE TIRE IS FLAT, we had better get it fixed before traveling.
13. I want to see the Corning Glass Museum BECAUSE I AM INTERESTED IN GLASS BLOWING.
14. When we get there, I WOULD LIKE TO LOOK AT THE DISPLAYS.
15. I would like to leave home early UNLESS THE TRAFFIC IS SLOW.
16. HE TOLD ME THE MUSEUM WAS CLOSED ON MONDAYS though it wasn’t listed on the schedule.
17. Even though it takes a long time to get there, WE WOULD STILL LIKE TO GO.
18. WHEN WE DROVE THERE, we got lost.
19. SINCE THE DISPLAYS WERE GREAT, I am glad we went.
20. IN CASE YOU ARE WONDERING HOW TO GET THERE, I will give you a map with the directions.