I was an eighth grader when I read my first banned book. [I was an eighth grader is an independent clause; when I read my first banned book is a dependent clause.]
Every subject-predicate word group in a sentence is a clause. Each sentence must contain at least one independent clause, with the exception of intentional sentence fragments such as exclamations.
Clauses may be connected by a coordinating conjunction, a subordinating conjunction, a relative pronoun, or a conjunctive adverb.
Peregrine falcons are about the size of a large crow, and they have a wingspread of three to four feet, [coordinating conjunction connecting two independent clauses]
It was hard to overcome my instinctive fear of their claws; nevertheless, I continued my hobby, [conjunctive adverb connecting two independent clauses] I like to raise falcons because they are such an independent breed, [subordinating conjunction connecting dependent clause to independent clause]
It was my grandfather who first interested me in these pets, [relative pronoun connecting dependent clause to independent clause]
A dependent clause may function as a noun, an adjective, or an adverb in a larger sentence. An independent clause may be modified by one or more dependent clauses.
Noun clauses function as subjects, subject complements, direct objects, or objects of prepositions.
A common rumor is that mosquitoes can carry the AIDS virus, [noun clause as subject complement]
An adjective clause modifies a noun or pronoun, which it usually follows. Adjective clauses ordinarily begin with a relative pronoun but occasionally begin with when, where, or why.
Amanda Smith, whom we met yesterday, showed us the house where she was born. [The first adjective clause modifies Amanda Smith; the second modifies house.]
An adverb clause is a dependent clause that modifies a verb, adjective, or adverb in another clause. Like adverbs, adverb clauses normally express ideas of time, place, condition, cause, manner, or comparison.
The rain stopped after we went home, [time]
The student union is located where the bookstore used to be. [place]
If we go back outdoors, the rain will start again, [condition]
The rain stopped because the weekend was over, [cause]
The rain stopped as suddenly as it started, [manner]
The new computer-aided weather forecasts are no more reliable than the old ones were, [comparison]
Adverb clauses are often introduced by subordinating conjunctions (because, when, where, since, though, and the like). If the adverb clause follows the main clause, a comma should not normally separate the two clauses. An adverb clause preceding the main clause should be set off by a comma.
Because the singer has such a high-pitched scream, the blare of the amplifiers is even more painful.
Placement of an adverb clause can change the emphasis of a sentence. Rock concerts are fun to attend unless the music is so loud it hurts your ears. Unless the music is so loud it hurts your ears, rock concerts are fun to attend. An adverb clause cannot act as the subject of a sentence.