A clause is a group of words containing a subject and a verb. 
A clause that can function as a sentence on its own is called an
independent clause:  

               e.g., My sister eats a lot of ice cream.

     While an independent clause may stand as a sentence by itself,
it  may also be combined with other independent clauses to form
compound sentences.  One way of connecting two independent clauses
is by using a comma and one of the seven coordinating conjunctions:
and, but, or, nor, for, yet, and so.  A good way to remember these
seven words is to use the word FANBOYS which contains one letter
for each of the seven conjunctions: For, And, Nor, But, Or, Yet,
So.  
               e.g., My sister likes ice cream, but she doesn't eat
                     it often.

     A dependent clause cannot function as a sentence by itself
because it begins with a subordinating word.  A dependent clause
may be a noun-clause, usually introduced by that or what, a
relative clause, beginning with who, which, or that or, most often,
an adverbial clause, introduced by an adverbial conjunction, such
as although, because, when, if, or even though:  

               e.g., because my sister likes ice cream  

     Because adverbial clauses are the most common, the rules
explained in this handout will be for punctuating independent
clauses and adverbial dependent clauses.  Adverbial clauses are
just like adverbs--they answer the questions when, where, or why.
Adverbial conjunctions introduce a condition, situation, or
explanation that relates a dependent clause to a main clause.  An
advervbial clause must be connected to an independent clause: 

                         [DC]                              [IC]
               e.g., Because my sister likes ice cream, she eats a
                     lot of it.
          

     There are four basic sentence types, containing different
combinations of independent and dependent clauses.  These are the
simple sentence, the compound sentence, the complex sentence, and
the compound-complex sentence.  

     In each of these, correct punctuation is considered very
important.  The rules for punctuating independent and dependent
clauses are summarized in the chart below.    

     The chart uses the following symbols: IC = independent clause,
DC = dependent clause, + = coordinating conjunction, < = adverbial
conjunction            


                      CLAUSE-CONNECTING RULES


                       ********************
                       *   1) IC.  IC.    *
                       *   2) IC; ic.     *
                       *   3) IC, + ic.   *
                       *   4) IC < dc.    *
                       *   5) < DC, ic.   *
                       ********************



The Simple Sentence (A sentence containing a single, independent
clause)

1. Ic.  Ic.  The commonest way of punctuating independent clauses
is to make each one a separate sentence, followed by end
punctuation: period (.),  question mark (?),  exclamation mark (!):

          Mark went to the supermarket.  He needed groceries for
     the week.

          The store was very crowded.  Apparently, there was a sale
     that day.

     Note: In the second example, the independent clause is
introduced by a transition: apparantly.  Such transitions, e.g.
however, therefore, indeed, do not make a clause dependent. 

*See On-line resource files: Transitions, Methods of Joining
Related Ideas

The Compound Sentence (A sentence of two or more independent clauses)

     Two independent clauses may be combined in the same sentence
in two ways.

2. Ic; ic.  Two independent clauses may be combined in one sentence
by connecting them with a semi-colon:  

          Mark spent half an hour in the soup aisle; all the labels
     looked alike.

     Note: because a semi-colon is not end-punctuation, the second
clause is not capitalized.



3. Ic, + ic. Two independent clauses may be combined in the same
sentence when connected by a comma and one of the seven
coordinating conjunctions (and, but, for, or, nor, yet, so):

          The fruit looked very fresh, but it was very expensive.

          Mark bought only a few apples, for he was on a strict  
     budget.


The Complex Sentence (A sentence combining an independent and a
dependent clause)

     Independent and dependent clauses may be combined in two ways. 
A dependent clause may come before or after an independent clause.

4. Ic < dc. When the independent clause comes first, no punctuation
is required to combine an independent and dependent clause in the
same sentence:

          Mark checked his list again before he got on line to
     check out.

          He didn't want to forget anything because he wouldn't
     have another chance to shop all week.


5. < Dc, ic. When the dependent clause comes first, a comma must be
placed before the independent clause:

          Because he was in a hurry, Mark helped the clerk bag his
     groceries. 

          As he was leaving the store, he saw his old girlfriend
     pushing a cart with two screaming children inside.


The Compound-Complex Sentence (at least one independent clause,
combined with any number of additional dependent and independent
clauses)

     As long as the rules explained above are followed, independent
and dependent clauses may be combined into sentences of multiple
clauses:

          When Mark got home, after he finished unloading the
     groceries, he found an extra $20 in his wallet, so he went
     back to return the money to the cashier.