Coordinate and Subordinate Clauses

 In this lesson we begin the discussion of clauses and clause structure within the sentence.  We start with coordinate and complex sentences. Note the terminology, as several terms are used interchangeably.



Coordinating conjunctions:  The most common coordinating conjunctions are 'and', 'but', 'so, 'for' and 'or'.
They can only join words or phrases of the same type.

In the first example the noun phrases are conjoined:

   [The dog] and [the boy] ran in the park.

In the following example the verb phrases are conjoined:

    The girl [ran into the park] and [played on the swings].

And in the next example two sentences are conjoined:

   [The boy read a book] and [the girl swam].

This last example is what is often called coordinate clause structure, as the two sentences (or clauses) are on an equal footing within the greater sentence.  Each clause is an independent clause.  A tree structure of this type of sentence looks something like this:

                                                                       S
                                                                    /   |   \
                                                                S  conj  S

Note that within the tree the two clauses (or sentences) are treated as equals.



Subordinate conjunctions:   They introduce a dependent clause.  Some common examples are:  'although', 'while', 'since', 'because', 'before', 'after', 'if', 'as', 'whenever'.   Clauses introduced by these words are also called subordinate clauses, meaning they are subordinate to the main sentence.  Another term for the kind of sentence containing this type of clause is a complex sentence.   So, a complex sentence consists of a combination of an independent clause and a dependent clause.

Here are some examples:

    [Although it was raining], Mary went for a walk.

    Mary went for a walk [while Matt vacuumed the livingroom].

Notice that for each of the above examples we could move the subordinate clause (with the subordinate conjunction firmly attached to the subordinate clause):

    Mary went for a walk [although it was raining].

    [While Matt vacuumed the livingroom], Mary went for a walk.

One distinction we can make between a coordinate conjunction and a subordinate conjunction is that the coordinate conjunction is quite independent.  It's not really attached to a clause.  The subordinate conjunction, however, is very much attached to the subordinate clause.

To illustrate this, if I take the coordinate clause structure above:  [The boy read a book] and [the girl swam].  I CANNOT do the following:     *[And the girl swam] [the boy read a book].

In other words, with the coordinate clause structure the two clauses can indeed exchange places:

                [The girl swam] and [the boy read a book].

But the coordinate conjunction stays where it is.  It is not attached to either clause.  If you look again at the Mary and Matt examples above you will see that the subordinate conjunction has to stay with the subordinate clause wherever it goes.

This type of subordinate clause is often referred to as an adverbial clause, because its function is like an adverb modifying the main clause (independent clause) of the sentence.
 

A tree structure of [Mary went for a walk while Matt vacuumed the livingroom] would look something like this:
 

                                                                       S
                                                                     /   \
                                                                  /         \
                                                            NP             VP
                                                               |               /  \     \
                                                           Mary        /    \            \
                                                                            /       \                \
                                                                          V      PP               adv. clause
                                                                           |     /      \                /            \
                                                                      went  Prep  NP       /               \
                                                                                    |       /  \       sub conj      S
                                                                               for   det N           |            /   \
                                                                                          |     |       while  NP      VP
                                                                                       a  walk               |        /      \
                                                                                                                    N      V          \
                                                                                                                     |       |                \
                                                                                                             Matt  vacuumed  NP
                                                                                                                                              /   \
                                                                                                                                           det    N
                                                                                                                                             |      |
                                                                                                                                         the  livingroom
 

Notice that the subordinate clause comes under the VP of the main sentence.  And it in turn is divided into the subordinating conjunction plus a sentence.

The following tree structure would then describe [While Matt vacuumed the livingroom, Mary went for a walk.]
 
 

                                                                S
                                                            /    |    \
                                                          /      |      \
                                           adv. clause  NP   VP
                                                /    \
                                sub conj        S

When the subordinate clause comes first, we can attach it to the main S.  When it comes last, we have to attach it to the main VP.  (Don't argue.  This is just the way it's done.)


This is the first type of subordinate clause that we will discuss in this class.  Complement clauses and relative clauses are on the agenda for future lessons.  (And I'm looking forward to them because they are my favorites.)


To return to Lesson 9, click here.