Clauses - simply

Look at the example of The Green Sports Car if you're in doubt about sentences.

Clauses and sentences can become very complicated, but this is a simple guide, so I'll keep it short.

A simple sentence would have a subject, a verb and an object.

To make it more interesting or more informative we can add information such as adjectives and adverbs

or we can combine two simple sentences to make one complex sentence.

The conjunction acts as a link for the two separate sentences. It joins them together into one. They are now smaller parts of a single sentence and we call them clauses. In this example two clauses are bound together by a conjunction to create a sentence.

Three types of sentences using clauses

Compound sentences have clauses linked by coordinating conjunctions such as and, or, but.
eg Anna likes Bob but Jim hit Will
Coordinating suggests a balance of equal weight between the two clauses

Complex sentences have clauses linked by subordinating conjunctions such as because, when, since.
eg Anna likes Bob because Jim hit Will
Subordinating suggests the second clause depends upon the first for its meaning

Complex sentences with relative clauses have clauses linked by relative pronouns such as who, which, whose, which, that.
eg Anna, who likes Bob, saw Jim hit Will
Relative suggests the clause has a relationship with another part of the sentence.

Three types of relative clause

A relative clause follows the noun it modifies.

In the sentence Anna, who likes Bob, saw Jim hit Will the section in parenthesis, who likes Bob, is the relative clause. The clause in this case is relative to the subject, Anna.

In the sentence Anna likes Bob, who is very handsome the relative clause is who is very handsome. The clause in this case is relative to the object, Bob.

In the sentence Anna hit Bob with a book, which was hard the relative clause is which was hard. The clause in this case is relative to the indirect object, the book.

Restrictive and non-restrictive relative clauses

In restrictive clauses the information is essential, while in non-restrictive clauses the information is not essential to the grammar and meaning of the sentence.