Self-Teaching Unit:

Comma Splices and Fused Sentences

© 2006, 1999, 1978 Margaret L. Benner   All rights reserved.

REVIEW                                                                                                       

 Before going on to compound and complex sentences, you should be thoroughly familiar with the simple sentence.  Here is a small review.

   In order to have a simple sentence (independent clause), you need these three elements:

          a subject                    a predicate verb                   a complete thought

      Example of simple sentence:

   A simple sentence is the same thing as an independent clause.

          Simple sentence                 =           Independent clause

Remember:  a simple sentence (independent clause) consists of a subject, a verb, and a complete thought.

Now this module will teach you about compound and complex sentences.

COMPOUND SENTENCES                                                                                

  The word compound means “to put together, to form a whole.”

Sometimes two independent clauses (two simple sentences) can be put together  to form another kind of sentence: the compound sentence. 

There are three patterns one may use to link simple sentences into a compound sentence.

Pattern #1:

  To see how to form a compound sentence this way, look at these two simple sentences.  

   They can be made into one compound sentence with a comma and one of these joining words (coordinating conjunctions):

for       and            nor             but            or            yet            so

If put together into a compound sentence, the two simple sentences above would look like any one of these:

 (The joining word or was not used in this compound sentence since the resulting sentence would not make sense.)

For, and, nor, but, or, yet, and so are joining words.  

They are also called coordinating conjunctions because they join or coordinate two equal clauses.

                                              MEMORIZE THEM!

One way to memorize them easily is to remember  FANBOYS:

Now click on the link below to do exercise 1.                             

Linkto Exercise 1.

Pattern #2:   

   Two independent clauses can also be joined into one compound sentence with a semicolon alone.  (Note:  You can use a comma between independent clauses only if you also use a coordinating conjunction.)

To learn how to form a compound sentence like this, look at these simple sentences.

They can be made into one compound sentence with a semicolon alone between the two independent clauses.

The semicolon has more strength than the comma.  Thus, it can separate two independent clauses by itself; a comma cannot separate two independent clauses unless it is followed by a coordinating conjunction (FANBOYS).

Now click on the link below to do exercise 2.                             

Link to Exercise 2

Pattern #3: 

  Still another way to form a compound sentence is to use a semicolon AND a conjunctive adverb between the two independent clauses.

Here is a list of the most frequently used conjunctive adverbs.

  You should become familiar with these words.

  To learn how to form a compound sentence with a conjunctive adverb and the correct punctuation, look at the original two simple sentences.  

These two sentences can be combined into a compound sentence with a semicolon,  appropriate conjunctive adverb, and comma.

Like the coordinating conjunction, each conjunctive adverb has an individual meaning; thus, you should use whichever one fits the sense of the sentence you are writing.

For example, see how the sentence’s meaning changes when therefore is substituted for however:

Why should you use compound sentences?

Sometimes it is better to use a compound sentence than a simple sentence.  For example, you may use a compound sentence because you want a variety of sentences in your writing.  In another instance, you may want to join two complete thoughts that are closely related in order to show your reader the relationship.

                                                                   (For more information on compound sentences, click on this link.)

Now click on the link below to do exercise 3.                             

Link to Exercise 3

REVIEW:  COMPOUND SENTENCES

To form a compound sentence, remember these rules for constructing it:

•   Use two independent clauses.

•   Join them with

            1.  an appropriate coordinating conjunction (FANBOYS)  

                 and place a comma in front of the conjunction;             

                                                          OR  

                2.  with a semicolon alone;

OR

               3.  with an appropriate conjunctive adverb (however, etc.), and

                    place a semicolon before the conjunctive adverb and  a 

                    comma after it.

  You might want to print these rules and diagrams into a notebook for future reference.

TWO MAJOR ERRORS:  COMMA SPLICES AND FUSED SENTENCES                   

   Compound sentences are correct only when constructed as shown in the previous four sections.

 This section discusses two major errors committed with compound sentences:

         X   the comma splice     and     X  the fused sentence

 Please read this section carefully so that you can recognize these errors and avoid them in your writing.

ERROR #1:  THE COMMA SPLICE

 Writers make this error when they try to separate the two independent clauses in a compound sentence with a comma alone.

 A comma is not a strong enough punctuation mark to separate the two independent clauses by itself; thus, using it causes the clauses to be spliced together.  

      Example of comma splice

 We can repair this comma splice in several ways:

  1.  We can add an appropriate coordinating conjunction (FANBOYS).  

  2.      We can change the comma to a semicolon.  

  3.      We can change the punctuation and add an appropriate conjunctive adverb.  

 The sentence below is another example of a comma splice.

We repair it by correcting the punctuation.  

 In each case above, we are forming a correct compound sentence by using patterns 1, 2, and 3 shown at the beginning of this module..

  ERROR #2:  THE FUSED SENTENCE

  Writers make this error by joining two independent clauses into a compound sentence without using any punctuation between them.

 No punctuation between the two independent clauses causes then to “fuse” into an INCORRECT compound sentence.  

    Example of a fused sentence

 We can repair a fused sentence the same way we repair a comma splice:

1.      Add an appropriate coordinating conjunction (FANBOYS).  

  2.  Place a semicolon between the two clauses.  

  3.  Add the needed punctuation and an appropriate conjunctive adverb.  

The sentence below is another example of a fused sentence.  

   We  can repair it by adding the necessary punctuation.  

   In each case above, we are forming a correct compound sentence by using the patterns shown   at the beginning of this module.

  Another way to repair a comma splice or fused sentence is, of course, to make each independent clause into a  single simple sentence.  

Now click on the link below to do exercise 4.                             

Link to Exercise 4  

Besides the simple sentence and the compound sentence, there is one other basic pattern

                                     The COMPLEX SENTENCE.

Note the difference:

             A simple sentence = 1 independent clause

              A compound sentence = 2 independent clauses (joined correctly!)

              A complex sentence = 1 independent clause joined to 1 dependent clause

Here is an independent clause (simple sentence):  

It contains a subject (Tom), a verb (saw), and a complete thought.

However, look at the following clause:

Because this group of words contains a subject-verb core (friend-read), it is a clause.

However, because it does not express a complete thought, it is NOT an independent clause.

We call such clauses dependent clauses because they depend on attachment to other sentence elements to be a complete thought.

Here is a list of words that begin dependent clauses.  They are called subordinating conjunctions. 
Become familiar with them.

  We can attach the dependent clause [after his friend read the novel] to the independent clause [Tom saw the movie} in two ways to make a sentence.

1.      Independent clause followed by dependent clause

2.      Dependent clause followed by independent clause  

Each sentence above is composed of two clauses – an independent clause and a dependent clause.

By attaching the dependent clause to an independent clause, we give the dependent clause the additional meaning it needs to be a complete thought.

A sentence composed of an independent clause and a dependent clause is called a COMPLEX SENTENCE.

Two basic patterns for the complex sentence are

1.      Independent clause  dependent clause.

2.      Dependent clause, independent clause.

Punctuation Rule:  Pattern #2 (dependent clause first) uses a comma between the clauses; pattern #1 (independent clause first) uses no comma between the clauses.

 Here are examples of each pattern above.

 EXAMPLES – Pattern #1

                  Independent clause        dependent clause.

EXAMPLES– Pattern #2

                  Dependent clause,  independent clause.

PUNCTUATION REMINDER:  When a complex sentence begins with the dependent clause, place a comma between the dependent clause and the independent clause.

                                                              (For more information on this kind of dependent clause, click on this link.)

Pattern #3

A third pattern for complex sentences puts the dependent clause IN THE MIDDLE of the independent clause.

EXAMPLE A

EXAMPLE B

PUNCTUATION NOTE:       In example A, no commas separate the dependent clause from the independent clause.  

        A child who has chickenpox should stay home from school.

 The dependent clause who has chickenpox is ESSENTIAL to the sentence.  In other words, who has chickenpox is needed to identify which child should stay home from school.

                                              BUT

 In example B, the dependent clause must be separated from the independent clause with commas.   

       Mary Jones, who has chickenpox, should stay home from school.

Here, the dependent clause is NOT ESSENTIAL to the sentence: the dependent clause is not needed to identify the child – Mary Jones.

For complex sentences using pattern #3, use commas to separate the dependent clause from the independent clause only if the dependent clause is not essential to the sentence's meaning.

If the dependent clause is essential, do not separate it from the rest of the sentence with commas.

                                                              (For more information on this kind of dependent clause, click on this link.)

Now click on the link below to do exercise 5.                             

Link to Exercise 5

  REVIEW                                                                                 

A single independent clause is a simple sentence.

Combining two independent clauses creates a compound sentence.

           3 ways to combine:

Combining a dependent clause and an independent creates a complex sentence.

         4 ways to combine:

  For additional review, click on this link.

SUMMARY

  Certainly it is important to know how to construct simple, compound, and complex sentences in order to write correct English sentences.  

However, it is also important to know these three kinds of sentences so that you can vary the sentence patterns in your writing.  

Choose this best sentence pattern for each individual writing instance, and thus use the written word to communicate most effectively.  

Click on the link below to do the Post Test.

Now do the post test