Grammarians and linguists point out two basic units that combine words for use in sentences. Phrases are groups like noun phrases, prepositional phrases, verb phrases, adjective phrases, and adverbial phrases. These groups of words are used in sentences, but they do not themselves have the internal stucture of sentences. A noun phrase has a noun plus all kinds of other things--determiners, adjectives, nouns, and more. But a noun phrase doesn't have a subject and predicate structure.
The other major unit is the clause. A clause is another name for a sentence. A simple sentence is also called an independent clause. Other clause types are used as parts of sentences. A dependent or subordinate clause is a sentence that has been changed to make it into a unit that can be combined with another sentence--to make a longer and more complex sentence. In the following example, an adverbial clause is added. The adverbial clause has the internal structure of a sentence--it has a subject and a predicate.
She will major in sociology because she wants to learn more about social structures.The Longman Student Grammar calls this type of clause a finite clause. The terms finite and nonfinite are widely used in linguistics and grammar studies to label important differences between clauses like the one in our example--with a full verb phrase that has "tense"--and other clauses that have the internal structure of sentences without having a full complete verb phrase.
Nonfinite Clauses as Adverbials
Nonfinite clauses can be used as adverbials. Infinitives are often used to give meanings in "reason" or "purpose" subcategories of the larger "process" category. In this example, the reason for the action is given with an infinitive:
John came to GSU to get a master's degree in TESL/TEFL.Participle clauses come in two types: those with -ing participles and those with -ed participles. They, too, have meanings in the process or manner category:
Tired from studying all afternoon, she went for a walk.Again, these clauses are called "nonfinite" because the verb phrases do not have tense. They are recognizably verb phrases (and actually predicates since they combine verb phrase with objects and even adverbials) but they have been changed to make them usable as sentence elements that we call "nonfinite clauses."
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