+361.+ We have found that there are two kinds of clauses, principal
clauses and subordinate clauses.
+A principal clause is one that does not depend on any word.+
+A subordinate clause is one that depends upon some word or words in the
principal clause.+
We have found, also, that these principal clauses are always connected
by co-ordinate conjunctions, for they are of equal rank and importance;
neither is dependent upon the other.
Subordinate clauses are always connected with the principal clause by a
subordinate conjunction. The subordinate clauses which we have been
studying have all been adverb clauses which are used to describe the
action expressed in the verb contained in the principal clauses.
The subordinate clause in a sentence may also be used as a noun. When
the subordinate clause is used as a noun it is called a noun clause.
+362.+ +A noun clause is a clause used as a noun.+
A noun clause may be used in any way in which a noun is used, except as
a possessive. It may be used as a subject, an object, a predicate
complement, or in apposition with a noun. These noun clauses may be
introduced by either relative pronouns, interrogative pronouns or by
conjunctions. For example:
I know _who_ he is.
He asked, "_what_ do you want?"
I know _where_ it is.
In the first sentence, _who he is_, is a noun clause used as the object
of the verb _know_. It tells _what_ I know, and is the object of the
verb _know_,--just as if I had said; _I know the facts_. In this
sentence the noun, _facts_, is the object of the verb _know_.
In the second sentence, _He asked, "what do you want?_" the noun clause
_what do you want_ is the object of the verb _asked_, and is introduced
by the interrogative pronoun _what_.
We will study in a subsequent lesson the use of noun clauses introduced
by relative pronouns. In this lesson we are studying the conjunctions.
In the last sentence, _I know where it is_, the noun clause _where it
is_, is the object of the verb _know_, and is introduced by the
conjunction _where_.
+363.+ Noun clauses are introduced by the subordinate conjunctions,
_where_, _when_, _whence_, _whither_, _whether_, _how_, _why_, and also
by the subordinate conjunction _that_. For example:
I know _where_ I can find it.
I inquired _when_ he would arrive.
We do not know _whence_ it cometh nor whither it goeth.
Ask _whether_ the train has gone.
I don't know _how_ I can find you.
I cannot understand _why_ he does so.
I believe _that_ he is honest.
In all of these examples the noun clauses are used as the objects of the
verb. Noun clauses may also be used as objects of prepositions. As, for
example:
You do not listen to _what is said_.
He talked to me about _what had happened_.
He told me to come to _where he was_.
+364.+ Noun clauses may also be used as the subject of a sentence. As
for example:
_That he is innocent_ is admitted by all.
_That he was guilty_ has been proven.
_Why he should do this_ is very strange.
_How we are to live_ is the great problem.
In all of these sentences, the noun clause is used as the subject of the
verb. You will note that most frequently the noun clause used as subject
of the verb is introduced by the subordinate conjunction _that_. But
quite often we write these sentences in a somewhat different way. For
example:
It is admitted by all _that he is innocent_.
It has been proven _that he was guilty_.
You will notice in these sentences we have expressed practically the
same thought as in the sentences where the noun clause was used as the
subject of the verb.
But now we have this little pronoun _it_ used as the subject, instead of
the clause, which is the real subject of the sentence. _It_ is simply
used as the introductory word in the sentence. The noun clause is in
reality the subject of the sentence.
+365.+ Noun clauses may also be used as the predicate complement with a
copulative verb. For example:
The general opinion is _that he is innocent_.
The problem is _how we may accomplish this quickly_.
The question was _why any one should believe such statements_.
In all of these sentences the noun clause is used as the complement of
the incomplete verbs _is_ and _was_, to complete the meaning, just as we
use a noun as the predicate complement of a copulative verb in such
sentences as, _Socialism is a science._ _War is murder._
+366.+ A noun clause may also be used in apposition to a noun to explain
its meaning. Apposition means to place alongside of. Note in the
following sentences:
The fact, _that such a law had been passed_, alters the situation.
His motion, _that the matter should be laid on the table_, was
adopted.
In the first sentence, the clause, _that such a law had been passed_, is
placed beside the noun _fact_ and explains _what_ that fact is. The
clause, _that the matter should be laid on the table_, is in apposition
to and explains the noun _motion_.
These noun clauses are used in apposition.