In grammar, a clause is a group of words consisting of a subject and a predicate, although, in non-finite clauses, the subject is often not explicitly given. In null subject languages there may not be a subject, either explicit or implicit. A clause is either a whole sentence or in effect a sentence-within-a-sentence.

Clauses are often contrasted with phrases, which do not express complete thoughts through combinations of subjects and predicates. Phrases generally do not contain verbs except as verbals (gerunds, participles, and infinitives).

Example:

• I didn't know that the dog ran through the yard.
  • through the yard is not a clause, but a phrase, since it has no subject or verb.
  • the dog ran through the yard is a clause; it is a whole sentence contained within a larger sentence.

Independent and dependent clauses

There are two basic categories of clauses: independent clauses and dependent clauses.

Independent clauses

An independent clause (or main clause, or coordinate clause) can stand by itself as a grammatically viable simple sentence. Multiple independent clauses can be joined (usually with a comma and a coordinating conjunction) to form a compound sentence.

Examples:

• I am a bus driver. (simple sentence)
• I drive a bus. (simple sentence)
• I am a bus driver, and I drive a bus. (compound sentence)
• I want to be an astronaut, but I haven't gotten my diploma. (compound sentence)
• I am a bus driver, but I want to be an astronaut. (compound sentence)
• Go to the store, and get me a copy of Planetside. (compound sentence) (Though a subject is not visible, in English the subject of an imperative is considered to be the pronoun 'you')

Dependent clauses

A dependent clause (or subordinate clause) cannot stand alone as a sentence. It usually begins with a subordinating conjunction or, in the case of an adverb or adjective clause (see below), a relative pronoun. A sentence with an independent clause and one or more dependent clauses is referred to as a complex sentence. One with two or more independent clauses and one or more dependent clauses is referred to as a compound-complex sentence.

Examples:

• My sister cried because she scraped her knee. (complex sentence)
  • Subjects: My sister, she
  • Predicates: cried, scraped her knee
  • Subordinating conjunction: because

• When they told me I won the contest, I cried, but I didn't faint. **(compound-complex sentence)
  • Subjects: they, I, I, I
  • Predicates: told me, won the contest, cried, didn't faint
  • Subordinating conjunctions: When, that (understood)
  • Coordinating conjunction: but

The above sentence actually contains two dependent clauses. "When they told me" is one; the other is "(that) I won the contest." The "that" is understood to precede the "I won" and functions as a subordinating conjunction.

Types of dependent clauses

Dependent clauses are often classified by their part of speech: a noun clause functions as a noun, an adjective clause functions as an adjective, and an adverb clause functions as an adverb.

Examples:

• That the kid was making so much money bothered me. (A noun clause is the subject of bothered.)
• Her eyes were a shade of blue that reminded me of the sea. (An adjective clause is modifying a shade of blue.)
• I have a tendency to hyperventilate when I'm upset. (An adverb clause is modifying the entire main clause.)

Syntax

Propozicio | Proposition (grammaire) | Clàs (gràmar) | 절 (언어) | 節 (文法) | Clause | Fråzlete