1. What is a Clause?

When a group of words, which has a subject and a predicate of its own, forms a part of a sentence, is called a Clause. It is, like, a small sentence which is a part of a bigger sentence.

Mr Chatterjee knew that I was ill.
The manager restarted the organisation after it had collapsed.

2. What is a Phrase?

When a group of words, that does not express a complete sense and contains neither a subject nor a finite verb, used as a single part of speech is called a Phrase.

Mr Chatterjee came to see me.
The company is on the verge of ruin.

3. Kinds of Clauses

Principal Clause

A clause that is not dependent on another clause and consists of a subject and a finite verb, is called a Principal Clause.

Mr Chatterjee knew where I was admitted.
I shall complete the essay if you help me with a few articles.

Co-ordinate Clause

When two or more clauses of the equal rank are connected by co-ordinating conjunctions, each clause is called a co-ordinating clause.

Subordinate or Dependent Clause

When a clause of a sentence depends on another clause of the sentence, the clause is called a subordinate or dependent clause. Subordinate clauses are of three kinds – I. Noun clause, II. Adjective clause & III. Adverbial clause.

Noun Clause

It works of a Noun; which means, it answers in a noun form to some word mentioned in another clause. So it can be started with that, what, when, how, etc. Thus, a noun clause may be a subject or an object of a verb; or, a complement to a verb; or, an object of a preposition; or apposition to a noun. e.g.,

That he was going to take revenge was known to all. (as a subject)
Why he did it is yet to reveal. (as a subject)
She told me that she would bring me The Arabian Nights. (as an object)
He exclaimed in disgust that it was rubbish. (as an object)
The truth is, he did not accept that. (complement to a verb)
He is the man who she unfriended with. (complement to a verb)
We know nothing of what they are going to do. (object of a preposition)
It depends on how we treat others. (object of a preposition)
It is in the air that government will provide the poor with accomodation. (apposition to a noun)
There was a hearsay that all kings used to drink with golden glasses. (apposition to a noun)

Adjective Clause

It qualifies some noun or pronoun in some other clause. Any adjective clause is introduced by either a relative pronoun (that, who, as, which) or a relative adverb (when, where, how, why, etc.)

Remember! If the adjective clause is used as an object, and the antecedent is not a doer in the sentence, the relative pronoun is often omitted.

This is the man who helped me.
This is the man (whom) I helped. (here, whom can be omitted)
She knew the place where I used to sit.
The ring (which) she bought has been lost. (here, which can be omitted)
All that glitters is not gold.

Adverbial Clause

It modifies some verb, adverb or adjective in some other clause. This clause can be used to modify time (when, while, before, after, till, until, since, etc), place (where, wherever, etc), cause or reason or purpose (as, because, since, that, so that, lest, in order to, who, which, etc), result or outcome (that, so-that, such-that, etc), manner (as), comparison or degree (than, so-as, such-as, as-as, etc.), condition or mood or conditional (if, whether, in case, on condition, etc.), compromise or concession (although, though, even, even if, etc.)

Strike while the iron is hot. (time)
The man had commited suicide before the Covid test report came. (time)
Return to the village wherever you live. (place)
Put the book where it was. (place)
I can not buy the shirt because it is expensive. (cause or reason)
I shall buy the shirt because my brother asked for it. (purpose)
Ravi who is out of the town can not join us. (cause)
I have bought a printer which would print all my worksheets. (purpose)
He is so tired that he is not coming with us. (result or outcome)
He did it so we gain more profit. (outcome)
Dress as you like. (manner)
He is taller than I. (comparison)
She is not so wise as her sister. (comparison)
He is sure to do this if he be permitted. (condition)
If I were a king, I should build a palace. (mood)
Were I be a king, I should build a palace. (mood)
Should I find her address, I would send her an invitation. (conditional)
Even if I fail in the exam, I shall not give up hope. (concession)
Though he is rich, he is dishonest. (concession)

4. Distinguish between Co-ordinate & Subordinate Clause

Co-ordinate means of the sane or equal rank. Subordinate means of a dependent rank. Hence a co-ordinate clause is a part of the sentence which is of an equal rank with another part of the sentence; or in other words, a co-ordinate clause does not depend for the completion of its sense on any other part of the sentence. It is an entire grammatical whole by itself. -P. Bhattacharyya

A subordinate clause, on the other hand, depends for the completion of its sense on the principal clause. It is not independent, that is, it cannot independently express a complete meaning. A co-ordinate clause is connected with the rest of the sentence by a co-ordinate conjunction while a subordinate clause must have a subordinate conjunction to connect it with the principal clause. -P. Bhattacharyya

Examples

	Co-ordinate Clause	Co-ordinating Conjunction	Co-ordinate Clause
1.	The moon arose	and	the Sahara glittered.
2.	She was invited	or	she would not go.
3.	She can sing well	but	she can not dance.
4.	He was ill	therefore	he did not join us.

	Principal Clause	Subordinating Conjunction	Subordinate Clause
1.	The Sahara glittered	when	the moon arouse.
2.	She is there	because	she was invited.
3.	She can sing	as well as	her sister.
4.	He could not join us	as	he was ill.
5.	You will be prosecuted	if	you trespass.

5. Kinds of Phrases

There are six kinds of phrases in English grammar.

Noun Phrase, Adjective Phrase, Adverbial Phrase, Prepositional Phrase, Conjunctional Phrase & Interjectional Phrase.

Noun Phrase

When a phrase expresses acts as a noun, it is called a Noun Phrase.

Spending time with family gives us real pleasure.
I like to write articles on different topics.

Adjective Phrase

When a phrase acts as an adjective, it is called an Adjective Phrase.

She wore a necklace of diamonds last night.
Virat is a player of fame.
A student desirous of success in life must work hard.

Adverbial Phrase

When a phrase acts as an adverb, it is called an Adverbial Phrase.

The given examples must be read with care.
The monkey fell from a banana tree.
She came to see me.

Prepositional Phrase

When a phrase acts as a preposition, it is called a Prepositional Phrase.

He could not join on account of illness.
The patient was at the point of death when he was taken to the hospital.
The company was on the verge of ruin.

Conjunctional Phrase

When a phrase acts as a conjunction, it is called a Conjunctional Phrase.

Scarcely had I reached the station when the train left.
Not only the man but his wife also is involved in the crime.
Join us as soon as you can.

Interjectional Phrase

When a phrase acts as an interjection, it is called an Interjectional Phrase.

What a mess!
Good Lord!
Oh Dear!

6. Verbal Phrase

For a few group verbs, the term Verbal Phrase is used.

A mad laughs at what he sees.
Never look down upon the poor.
She seems coming across to me for the fourth time this year.