There are two main types of clauses: independent clauses, which can function independently as sentences, and dependent clauses, which depend on an independent clause to form a sentence.
We’ll briefly cover the various types of clauses below. To learn more about how clauses are formed and used, continue on to each individual section.
An independent clause (also known as a main clause) is a clause that forms a complete, independent thought. It does not require anything else to be considered complete, and so it can stand alone as a sentence.
- “I refuse.”
- “They like to stay in fancy hotels.”
- “The girl in the red jacket ran quickly towards the bus.”
- “The Beatles were a great band.”
- “I wish it weren’t Monday.”
In each of the above cases, the independent clause remains able to stand alone as a simple sentence.
Sometimes we form a sentence with two (and occasionally more) independent clauses, which is known as a compound sentence. We join the independent clauses together with a comma and a conjunction or a semicolon without a conjunction. For example:
- “She wanted to play tennis, but he wanted to play basketball.”
- “My brother lives in Detroit; I wish I lived there.”
A dependent clause (also called a subordinate clause) is a clause that relies on the information from an independent clause to form a complete, logical thought. As such, it cannot stand on its own to form a sentence.
- “Whenever I travel, I like to stay in fancy hotels.”
- “We struck up a great conversation with a person whom we met on the plane.”
- “She found it strange that they like to eat sushi.”
In each of the examples above, the groups of words in bold are clauses, because they each have a subject (I, we, and they) and a predicate (travel, met on the plane, and like to eat sushi). However, we can also see that they are dependent clauses because of their dependent words—whenever, whom and that. Because of this, they cannot stand alone as a sentence; they depend on the information from the independent clauses (in italics) to be logically complete.
Categories of Dependent Clauses
Because dependent clauses must be a part of or attached to an independent clause, they serve a variety of grammatical functions depending on what type of dependent clause we are using. There are three primary categories of dependent clauses: noun clauses, relative clauses, and adverbial clauses. We’ll look at a few examples of each. To learn more about them, continue on to the section Dependent Clauses, or to the individual sections for each type of clause.
Noun clauses are dependent clauses that function as nouns. Because of this, noun clauses can perform all the roles that a normal noun could play in a sentence, such as the subject or the object of a verb. For example:
- “Wherever we decide to go is fine with me.” (subject of the sentence)
- “I want to see what is available before I make a purchase.” (direct object of the verb see)
Relative clauses, also called adjective clauses, provide descriptive information about a noun. These clauses can either be essential to the sentence (restrictive clauses) or non-essential (non-restrictive clauses). They are introduced by either a relative pronoun or a relative adverb.
Here are some examples:
- “The man, whom I’d heard so much about, gave an electrifying speech to the crowd.” (non-restrictive clause)
- “The book that I wrote is being published in January.” (restrictive clause)
- “Any student whose desk is not clean will have detention after class.” (restrictive clause)
- “I love casual Fridays, when we get to wear jeans to work.” (non-restrictive clause)
An adverbial or adverb clause is used, like a regular adverb, to modify adjectives, verbs, adverbs, and sometimes entire clauses. Adverbial clauses use subordinating conjunctions to connect to an independent clause. For example:
- “I went to the park before my parents woke up.” (modifies the verb went)
- “Animals are cute while they’re young.” (modifies the adjective cute)
- “I work better when I have total privacy.” (modifies the adverb better)
- “I have loved you since the day I met you.” (modifies the entire clause I have loved you)
Omitted subjects in imperative sentences
Every clause in English must have both a subject and a predicate. However, when we form imperative sentences to issue commands or requests, the subject is always implied because the sentence is directed at someone specific (either the reader or the person being spoken to). In this case, we never include the subject. For example:
- “Do your homework!”
- “Please open the window.”
- “Let me know when the documents arrive.”
We sometimes include a person’s name to specify who is being addressed, but this is not the same as the subject of the sentence. It is known as a noun of address (also known as a vocative), which is considered parenthetical and set apart by commas. For instance:
- “John, do your homework!”
- “Please open the window, Mary.”
- “Let me know when the documents arrive, sir.”