The Grammar Hierarchy

It can be helpful to think of English language consisting of a hierarchy:

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Sentences, clauses and phrases

A sentence expresses a complete idea.  A written sentence usually begins with a capital letter and ends with a full stop, question mark or exclamation mark.

A sentence usually has a “subject” and a “predicate”.

The subject is a noun or pronoun identifying the person or thing that the sentence is about – often the person or thing that performs the action of the verb. 

The predicate is everything else in a sentence apart from the subject.

A clause also expresses a complete idea. It can be a complete sentence or part of a sentence.

A clause usually includes a “subject” and a “predicate”.

A clause that is used as a complete sentence is called an “independent clause”.

When there is more than one clause in a sentence, at least one is the “main clause” while the others might be “subordinate clauses” (or “subsidiary clauses”).

A phrase is a group of words that does not contain both a subject and a verb, and therefore does not express a complete idea.

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The grammatical hierarchy illustrated

Word:

woman

Phrase:

the young woman

This has a noun, which might be a subject, but no verb. It therefore does not express a complete idea.

Clause:

the young woman answered the question

This could be an independent clause and used as a complete sentence.

Simple sentence:

The young woman answered the question.

This sentence has just one clause.

Complex sentence:

After she had thought for a while, the young woman answered the question.

This sentences has a main clause: the young woman answered the question, and a subsidiary clause: after she thought for a while.

Compound sentence: 

The young woman answered the question and the audience applauded. 

This sentence has two main clauses – the young woman answered the question and the audience applauded. Both could be independent clauses and complete sentences: The young woman answered the question. The audience applauded. They have been joined together by the conjunction “and”, to make things flow better.