In grammar

Grammar

In linguistics, grammar is the set of structural rules that govern the composition of clauses, phrases, and words in any given natural language. The term refers also to the study of such rules, and this field includes morphology, syntax, and phonology, often complemented by phonetics, semantics,...

, a clause is the smallest grammatical unit that can express a complete proposition

Proposition

In logic and philosophy, the term proposition refers to either the "content" or "meaning" of a meaningful declarative sentence or the pattern of symbols, marks, or sounds that make up a meaningful declarative sentence...

. In some languages it may be a pair or group of words that consists of a subject

Subject (grammar)

The subject is one of the two main constituents of a clause, according to a tradition that can be tracked back to Aristotle and that is associated with phrase structure grammars; the other constituent is the predicate. According to another tradition, i.e...

 and a predicate

Predicate (grammar)

There are two competing notions of the predicate in theories of grammar. Traditional grammar tends to view a predicate as one of two main parts of a sentence, the other being the subject, which the predicate modifies. The other understanding of predicates is inspired from work in predicate calculus...

, although in other language

Language

Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...

s in certain clauses the subject may not appear explicitly as a noun phrase

Noun phrase

In grammar, a noun phrase, nominal phrase, or nominal group is a phrase based on a noun, pronoun, or other noun-like word optionally accompanied by modifiers such as adjectives....

, being instead marked on the verb (this is especially common in null subject language

Null subject language

In linguistic typology, a null-subject language is a language whose grammar permits an independent clause to lack an explicit subject. Such a clause is then said to have a null subject. Typically, null subject languages express person, number, and/or gender agreement with the referent on the verb,...

s). The most basic kind of sentence

Sentence (linguistics)

In the field of linguistics, a sentence is an expression in natural language, and often defined to indicate a grammatical unit consisting of one or more words that generally bear minimal syntactic relation to the words that precede or follow it...

 consists of a single (independent) clause. More complex sentences may contain multiple clauses, including clauses contained within clauses. Clauses may be independent

Independent clause

An independent clause is a clause that can stand by itself, also known as a simple sentence. An independent clause contains a subject and a predicate; it makes sense by itself....

 or dependent

Dependent clause

In linguistics, a dependent clause is a clause that augments an independent clause with additional information, but which cannot stand alone as a sentence. Dependent clauses modify the independent clause of a sentence or serve as a component of it...

. Independent clauses are those that could stand as a sentence by themselves, although they may be used connected with other clauses in a longer sentence. Dependent clauses are those that would be awkward or nonsensical if used alone, and must be used in a sentence also containing an independent clause.

Clauses are often contrasted with phrase

Phrase

In everyday speech, a phrase may refer to any group of words. In linguistics, a phrase is a group of words which form a constituent and so function as a single unit in the syntax of a sentence. A phrase is lower on the grammatical hierarchy than a clause....

s. Traditionally, a clause was said to have both a finite verb

Finite verb

A finite verb is a verb that is inflected for person and for tense according to the rules and categories of the languages in which it occurs. Finite verbs can form independent clauses, which can stand on their own as complete sentences....

 and its subject, whereas a phrase either contained a finite verb but not its subject (in which case it is a verb phrase

Verb phrase

In linguistics, a verb phrase or VP is a syntactic unit composed of at least one verb and the dependents of that verb. One can distinguish between two types of VPs, finite VPs and non-finite VPs . While phrase structure grammars acknowledge both, dependency grammars reject the existence of a...

) or did not contain a finite verb. Technically, a phrase is any group of words that fuction together as a single part of speech. Hence, in the sentence "I didn't know that the dog ran through the yard," "that the dog ran through the yard" is a clause, as is the sentence as a whole, while "the yard," "through the yard," "ran through the yard," and "the dog" are all phrases. However, modern linguists do not draw the same distinction, as they accept the idea of a non-finite clause

Non-finite clause

In linguistics, a non-finite clause is a dependent clause whose verb is non-finite; for example, many languages can form non-finite clauses from infinitives...

, a clause that is organized around a non-finite verb

Non-finite verb

In linguistics, a non-finite verb is a verb form that is not limited by a subject and, more generally, is not fully inflected by categories that are marked inflectionally in language, such as tense, aspect, mood, number, gender, and person...

.

Structures of dependent clauses

Dependent clauses may be classified by their structure, although this classification does make some reference to the clause's function in a sentence. This scheme is more complex than analysis by function, as there are many different ways that a dependent clause can be structured. In English. Common structures include the following:

• Many dependent clauses, such as "before he comes" or "because they agreed," consist of a preposition-like subordinating conjunction, plus what would otherwise be an independent clause. These clauses act much like prepositional phrases, and are either adjective clauses or adverb clauses, with many being able to function in either capacity.
• Relative clause
  Relative clause
  A relative clause is a subordinate clause that modifies a noun phrase, most commonly a noun. For example, the phrase "the man who wasn't there" contains the noun man, which is modified by the relative clause who wasn't there...
  
  s, such as "which I couldn't see," generally consist of a relative pronoun
  Relative pronoun
  A relative pronoun is a pronoun that marks a relative clause within a larger sentence. It is called a relative pronoun because it relates the relative clause to the noun that it modifies. In English, the relative pronouns are: who, whom, whose, whosever, whosesoever, which, and, in some...
  
  , plus a clause in which the relative pronoun plays a part. Relative clauses usually function as adjective clauses, but occasionally they function as adverb clauses; in either case, they modify their relative pronoun's antecedent and follow the phrase or clause that they modify.
• Fused relative clauses, such as "what she did" (in the sense of "the thing she did"), are like ordinary relative clauses except that they act as noun clauses; they incorporate their subjects into their relative pronouns.
• Declarative content clause
  Content clause
  In grammar, a content clause is a subordinate clause that provides content implied by, or commented upon by, its main clause. The term was coined by Otto Jespersen...
  
  s, such as "that they came," usually consist of the conjunction that plus what would otherwise be an independent clause, or of an independent clause alone (with an implicit preceding that). For this reason, they are often called that-clauses. Declarative content clauses refer to states of affairs; it is often implied that the state of affairs is the case, as in "It is fortunate that they came," but this implication is easily removed by the context, as in "It is doubtful that they came."
• Interrogative content clauses, such as "whether they came" and "where he went" (as in "I don't know where he went"), are much like declarative ones, except that they are introduced by interrogative word
  Interrogative word
  In linguistics, an interrogative word is a function word used for the item interrupted in an information statement. Interrogative words are sometimes called wh-words because most of English interrogative words start with wh-...
  
  s. Rather than referring to a state of affairs, they refer to an unknown element of a state of affairs, such as one of the participants (as in "I wonder who came") or even the truth of the state (as in "I wonder whether he came").
• Small clause
  Small clause
  In some descriptions of grammar, small clauses are minimal predicate structures: they possess arguments and predicates but no tense. Small clauses usually occur within the context of full clauses and may act as the direct object of the verb. In the examples below, the small clause is italicized...
  
  s, such as "him leave" (as in "I saw him leave") and "him to leave" (as in "I wanted him to leave"), are minimal predicate structures, consisting only of an object and an additional structure (usually an infinitive
  Infinitive
  In grammar, infinitive is the name for certain verb forms that exist in many languages. In the usual description of English, the infinitive of a verb is its basic form with or without the particle to: therefore, do and to do, be and to be, and so on are infinitives...
  
  ), with the latter being predicated to the former by a controlling verb or preposition.

See also

• Adverb clause
• Dependent clause
  Dependent clause
  In linguistics, a dependent clause is a clause that augments an independent clause with additional information, but which cannot stand alone as a sentence. Dependent clauses modify the independent clause of a sentence or serve as a component of it...
  
  
• Relative clause
  Relative clause
  A relative clause is a subordinate clause that modifies a noun phrase, most commonly a noun. For example, the phrase "the man who wasn't there" contains the noun man, which is modified by the relative clause who wasn't there...
  
  
• Sentence (linguistics)
  Sentence (linguistics)
  In the field of linguistics, a sentence is an expression in natural language, and often defined to indicate a grammatical unit consisting of one or more words that generally bear minimal syntactic relation to the words that precede or follow it...
  
  
• T-unit
  T-unit
  In linguistics, the term T-unit was coined by Kellogg Hunt in 1965. It is defined as the "shortest grammatically allowable sentences into which or minimally terminable unit." Often, but not always, a T-unit is a sentence....
  
  
• Thematic equative
  Thematic equative
  In systemic functional grammar, a thematic equative is a thematic resource in which two or more separate elements in a clause are grouped together to form a single constituent of the theme-plus-rheme structure...
  
  
• Balancing and deranking
  Balancing and deranking
  In linguistics, balancing and deranking are terms used to describe the form of verbs used in various types of subordinate clauses and also sometimes in co-ordinate constructions....