Detailed Table of Contents
Sentences
A sentence is a collection of words arranged to make a complete thought. Each sentence has a subject, which the sentence is about, and a predicate, which is an action or state relating to the subject. A sentence must express a complete thought. A sentence must make sense on its own:

When he was in school.
I knew him when he was in school.
Christopher's father.
The man who came to the door was Christopher's father.

Sentences are constructed from clauses. A sentence may have exactly one clause, or it may consist of several.
Sentences may be grouped to form paragraphs.

Clauses
A clause is a major part of a sentence. A clause contains a subject and a predicate. There are two main types of clauses.
Independent clauses are complete thoughts and can stand alone as sentences.
Dependent clauses support independent clauses but cannot stand alone.


Dependent Clauses
A dependent clause cannot stand by itself. Dependent clauses are usually introduced by conjunctions:

Because we were tired, we went to bed early.

-- "Because we were tired" is the dependent clause.

To be complete, a sentence must contain an independent clause; the dependent clause is optional.
A sentence may contain several dependent clauses, usually separated by commas:

Because we were tired, and had nothing to do, we went to bed early.

-- Both "because we were tired" and "and had nothing to do" are dependent clauses.

In sentences containing more than one clause , the subject of each clause should be the same or at least closely related:

I met Sandra at the party and the music was very loud.

This problem can be corrected by rewriting to use two sentences or by rewriting so the same subject is used throughout:

I met Sandra at the party. The music at the party was very loud.

-- Two sentences are preferable since two distinct ideas are being expressed

I met Sandra at the party and I thought the music was very loud.

Independent Clauses
An independent clause can stand alone as a complete sentence:

We went to bed early because we were tired.

-- "We went to bed early" is the independent clause.

I received your letter and opened it immediately.

-- "I received your letter" is the independent clause.

A sentence may contain several independent clauses, joined by commas and conjunctions or semicolons:

We went to bed early, yet we were not tired.
I wanted to mow the lawn, but the lawnmower was broken.
I called her yesterday; she was not at home.

A sentence may contain an independent clause and one or more dependent clauses:

We went to bed early because it was dark.
I received your letter, opened it, but didn't read it.
The wind howled through a mouse-sized hole in the door on the night of the great flood.



Objects
The object is the thing acted on by the subject, the thing on which the subject acts, or the condition of the subject:

John kicked the ball.

-- "Ball" is the object (the subject John acts on the object)

The ball hit John.

-- "Ball" is the object (the object acts on the subject John)

John is happy.

-- "Happy" is the object (the object is the condition of the subject John)


Paragraphs
A paragraph is a collection of sentences, all of which contribute to a single theme. Each paragraph should have one -- and only one -- point to make.
Phrases
A phrase is a collection of words that modifies or connects. A phrase does not contain both a subject and a verb:

by the time
we will have
he had not
Predicates
The predicate expresses action about or the condition of the subject of a sentence or clause. The predicate contains a verb, object, and modifiers such as adjectives and adverbs:

I read the report yesterday.

-- The predicate is "read the report yesterday."

The black bear reared up on its hind paws.

-- The predicate is "reared up on its hind paws."

Because we were tired, we went to bed.

-- The predicate of the independent clause is "went to bed." The predicate of the dependent clause is "were tired."
Subjects
The subject is the person, place, thing, or idea about which a sentence or clause is written:

We went to bed.

-- "We" is the subject.

She wore the dress that she wore last week.

-- "She" is the subject.

I don't like the new policies.

-- "I" is the subject.

The subject of a sentence is contained in the sentence's independent clause.