A clause is an organized group of words with a subject and a verb.
A main clause is an independent clause, which can stand alone as a complete sentence.
A subordinated clause is a dependent clause and is not complete.
A sentence can have a main clause and a subordinate clause to form a complex sentence. A main clause can combine with another main clause to form compound sentences. A compound sentence can combine with another subordinate clause to form a compound-complex sentence.
Types of Clauses
1. INDEPENDENT CLAUSE
An independent or main clause has a subject, a verb and can stand alone as a sentence.
Example: Canada is a very large country.
2. SUBORDINATE CLAUSES
A subordinate clause depends on the main clause that it often modifies. A subordinate clause has a subordinator that usually introduces the clause such as subordinating conjunctions (as, since, because) or relative pronouns (who, which, that). They are sometimes called dependent clauses because they "depend" on a main clause to give them meaning. A subordinate clause does not express a complete thought, so it does not stand alone, however they normally act as single part of speech. Subordinate clauses can be identified as adjective clauses, adverbial, relative clauses, participle clauses, to-infinitive clauses, and nominal clauses.
Examples: Fred knew that I wanted a new ball.
3. ADVERBIAL CLAUSES
An adverb is a word belonging to a class of words which modify any constituent class of words other than nouns, such as verbs, adjectives, adverbs, phrases, clauses, or sentences. An adverbial clause is a clause that has an adverb-like function in modifying another clause similar to the way adverbs modify verbs. Adverbial clauses can modify an entire independent clause or another subordinate clause to which they might be attached. Adverbial clauses describe time of the event, place of the event, manner of the event, cause of the event or condition for the event. Most adverb clauses can be recognized because they are introduced by subordinating conjunctions: after, before, until, while, because, since, as, so that, in order that, if, unless, whether, though, although, even though and where.
I haven't been skating since we all went up to Banff last winter.
He stood there as if he was frozen to the very spot.
Fred jogs where there is no traffic because he likes it.
4. RELATIVE CLAUSES
A relative clause is a subordinate clause that modifies nouns and sometimes indefinite pronouns. The antecedent of the relative clause can be the subject of the main clause, or its object. Relative clauses are adjectival and they occur after the modified noun. Relative clauses give essential information to define or identify the person or thing we are talking about. Relative clauses are introduced by relative pronouns “that, who, which, whom and whose” or relative adverbs "when, where, why".
I saw the player [who hit you].
I saw the player [that hit you].
I like the park [where I jog].
I would like to know the reason [why you didn't eat the vegetables].
There are two different types of relative clause a "defining" or identifying clause, which tells us which person or thing we are talking about and a "non-defining" or non-essential clause, which gives us more information about the person or thing we are talking about.
5. NOUN CLAUSES
Nominal clauses function as nouns and may be replaced with a pronoun. Like a noun, a nominal clause names a person, place, thing, or idea. A nominal clause may function in a sentence as a subject, subjective complement, appositive, object of preposition, direct object or indirect object. Nominal clauses are subordinated by one of the following subordinating conjunctions: how, that, what, when, where, whether, which, who and why.
[How you did it] is not my concern. (That is not my concern)
[That I wanted a ball] was irrelevant in the discussion. (It was irrelevant)
An interrogative beginning a nominal clause, has a function within the nominal clause. Nominal clauses may begin with interrogatives: who, whom, what, which, whoever, whomever, whatever, when, where, how and why.
Example: Why you did that is a mystery to us.
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