Improving Your Sentence Structure

Lessons
Cat and dog sentences Dangling participles Misplaced modifiers Faulty parallel structure
Pronoun-antecedent disagreement Run-on sentences Sentence fragments Subject-verb disagreement

Rationale for this unit

Of all the topics in this course, this is the one with which writers have the greatest difficulty. If you do not understand the structure of a sentence, you aren't able to see mistakes in your writing. Master this subject, and you will be able to detect errors in reports, books, newspapers, magazines, and conversations.

Sentence

A sentence must have a subject and a predicate. The subject informs the reader who or what the sentence is about; the predicate informs the reader what the subject is doing.

The drunken man staggered down the sidewalk.

To find the subject, you read the sentence and ask "Who or what is this sentence about?" The answer is the drunken man.

To find the predicate, you ask "What did the subject do?" The answer is staggered down the sidewalk.

Simple subject and simple predicate

The simple subject is usually one word (a noun or a pronoun), while the simple predicate is the verb.

The simple subject in the above sentence is man and the simple predicate is staggered. The other words in the sentence are modifiers, which tell us more about the simple subject man and the simple predicate staggered.

Complete subject and complete predicate

The complete subject consists of the simple subject and all of its modifiers, which in this sentence is the drunken man.
The complete predicate consists of the simple predicate and all of its modifiers, which in this sentence is staggered down the sidewalk.

Principal clause and subordinate clause

You must be able to distinguish between a principal clause and a subordinate clause.

A principal clause must have a subject and a verb, and it must make sense by itself.

The drunken man staggered down the sidewalk.

A subordinate clause also must have a subject and a verb, but it does not make sense by itself. It is subordinate to the principal clause.

because he was drunk

This clause has a subject he and a verb was, but it does not make sense by itself. You need to ask "What happened because he was drunk?"

We can combine the principal clause and the subordinate clause to form a complete sentence.

Because he was drunk, the man staggered down the sidewalk.

Compound sentence

A compound sentence will have at least two principal clauses joined by a coordinate conjunction.

The drunken man thought he was safe, but he was arrested by the police.

These are two principal clauses because both clauses make sense by themselves.
The two principal clauses are The drunken man thought he was safe and He was arrested by the police.

Complex sentence

A complex sentence has a principal clause and a subordinate clause.

Because he was drunk, the man staggered down the sidewalk.

The subordinate clause is Because he was drunk and the principal clause is the man staggered down the sidewalk.

General comments

1. Not all sentences are as simple as The drunken man staggered down the sidewalk.

In some sentences, the predicate may come before the subject. This is called an inverted sentence.

Down the sidewalk staggered the drunken man.

2. The subordinate clause could be in the middle of the sentence.

Richard Cory, whom everyone envied, was not really happy.

3. The subject of the sentence might not be stated but, rather, understood.

Open the door.

Although it is not stated, it is understood that the subject is you. Therefore, the complete sentence is You open the door. The speaker is giving a command to someone.

4. Do not confuse a phrase with a clause.

A phrase is a group of words that do not have a subject and a predicate.

down the road

A clause is a group of words that do have a subject and a predicate.

as he staggered down the road


For an explanation of each of the eight lessons in Improving Your Sentence Structure, see Sentence Structure Terms Explained.