All sentences consist of one or more clauses. A clause is a group of words that contains a subject and a verb. Some clauses are independent while others are dependent, and for a sentence to be complete, it must contain at least one independent clause. (For more information, see the Sentence Structure Basics tip sheet.)
This tip sheet will discuss two types of dependent clauses: subordinate clauses and adjective clauses.
Subordinate clauses are clauses that begin with subordinating conjunctions. Subordinating conjunctions are words or phrases that help to bring ideas together by showing cause and effect, time relationships, opposition, and condition. Here are some examples of subordinating conjunctions:
|Although||Though||Every time (that)||Until|
|When||Since||Provided (that)||Whether or not|
|If||As soon as||After||In case|
|Before||Once||Now that||As/So long as|
Here is an example of how a subordinating conjunction can fit into a subordinate clause:
|This subordinate clause is not a complete sentence. It needs to be combined with an independent clause.|
Here are some examples of how a subordinating clause can fit into a sentence:
Sentences 1 and 2 are both complete sentences. Each consists of a subordinate clause that is combined with an independent clause.
Punctuation rule: If a subordinate clause comes before an independent clause (as in sentence 1), you must put a comma after the subordinate clause. If a subordinate clause comes after an independent clause (as in sentence 2), you must not put a comma between the clauses.
Adjective clauses are dependent clauses that modify (describe or identify) nouns. An adjective clause includes a relative pronoun that stands in for the noun being modified. Depending on the sentence, the relative pronoun may function as the subject of the clause, the object of the verb, or the object of a preposition. Here are some examples of relative pronouns:
Who That Which Whom Whose
|This adjective clause is not a complete sentence. It needs to be combined with an independent clause containing the noun
that it modifies. Adjective clauses may follow independent
clauses, or they may interrupt them.
Here are some examples of adjective clauses in sentences:
|Sentence 1 is complete. It consists of an independent clause and an adjective clause that describes the noun beach.|
Sentence 2 has the same meaning as sentence 1.
|When the noun being modified is a person, either who or that may be used. Sentences 3 and 4 have the same meaning.|
|Sentence 5 demonstrates another way to express essentially the same idea. Here, the adjective clause interrupts the independent clause.|
|In this clause, the relative pronoun who is the object of the verb met.|
When the relative pronoun is used as the object of the verb, the adjective clause can take several forms.
|If the noun being modified is a person, you many use who or whom.
(If the noun being modified is a thing, you may use which.)
|You may use that.|
|You may omit the relative pronoun.|
It is important to always place an adjective clause pronoun as close as possible to the noun it modifies. If you place the adjective clause beside a noun it is not meant to modify, you will create a “misplaced modifier” error, which could change the meaning of your sentence and cause confusion for your reader. Here is an example of how a misplaced modifier error can change meaning :
This sentence suggests that I met you at the bookstore rather than the woman.
|In this clause, the relative pronoun which is the object of the preposition for.|
When the relative pronoun is used as the object of a preposition, the adjective clause can take several forms.
The most formal way to express these ideas is to place the preposition at the beginning of the adjective clause as in sentences 1 and 2 (below). In this type of sentence construction, if the noun being modified is a person, you must use "whom." If the noun being modified is a thing, you must use "which."
The more common way to express these ideas is to place the preposition after the subject and verb of the adjective clause as in sentences 3, 4, and 5 (below). In this type of sentence construction, the adjective clause can take several forms.
You may use "which."
(if the noun being modified is a person, you may use "who" or "whom."
|You may use "that."|
|You may omit the relative pronoun.|
|The relative pronoun whose is used to demonstrate possession. It may be used to modify people or things.|
|Both whose and the noun to which it is connected (in sentence 1, dog; in sentence 2, language) must always be placed at the beginning of the adjective clause.|
You should not use commas around adjective clauses if the adjective clause is necessary to identify the noun being modified.
|Sentence 1 does not take commas because the adjective clause identifies the noun cake. The cake in this sentence is identified as the cake that Sara made.|
You should use commas around adjective clauses if the adjective clause is not necessary to identify the noun being modified; that is, if it just gives extra information about the noun.
|Sentence 2 takes commas because the adjective clause does not identify the noun cake. The cake in this sentence is identified as my birthday cake;|
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