Although nouns and adjectives most frequently function as the subject complement of sentences, five grammatical forms can perform the grammatical function of subject complement in the English language. Both native speakers and ESL students must learn and understand the five forms that can function as the subject complement in order to speak and write English fully and correctly. The five grammatical forms that can function as the subject complement are:
- Noun phrases
- Adjective phrases
- Prepositional phrases
- Verb phrases
- Noun clauses
Subject complements are defined as words, phrases, and clauses that follow a copular or linking verb and refer back to modify or describe the subject. Subject complements are grammatical constituents embedded in the predicate of clauses.
Noun Phrases as Subject Complements
The first grammatical form that can perform the grammatical function of subject complement is the noun phrase. Noun phrases are defined as phrases that consist of a noun or pronoun plus any modifiers or complements. For example, the following italicized noun phrases function as subject complements:
- My favorite subject is grammar.
- The professor is an exceptionally intelligent person.
- My sister became a mother last night.
Traditional grammars generally use the term predicate nominative to refer to noun phrases functioning as subject complements.
Adjective Phrases as Subject Complements
The second grammatical form that can perform the grammatical function of subject complement is the adjective phrase. Adjective phrases are defined as phrases that consist of an adjective plus any modifiers or complements. For example, the following italicized adjective phrases function as subject complements:
- Grammar sometimes seems difficult.
- Grammar actually is quite simple.
- The pie tastes very sour.
Traditional grammars generally use the term predicate adjective to refer to adjective phrases functioning as subject complements.
Prepositional Phrases as Subject Complements
The third grammatical form that can perform the grammatical function of subject complement is the prepositional phrase. Prepositional phrases are defined as phrases that consist of a preposition directly followed by a prepositional complement. For example, the following italicized prepositional phrases function as subject complements:
- The darkest time of night is after midnight.
- Grammar is out of this world.
- The grimiest place is under the freezer.
Verb Phrases as Subject Complements
The fourth grammatical form that can perform the grammatical function of subject complement is the verb phrase in the form of present participles and infinitives. Verb phrases are defined as phrases that consist of a verb plus any modifiers, complements, particles, or infinitive markers. For example, the following italicized verb phrases function as subject complements:
- The assignment is to read about subject complements.
- Her favorite pastime is gardening.
- Your only responsibility is babysitting your younger siblings.
Traditional grammars generally use the term gerund to refer to verb phrases functioning as subject complements.
Noun Clauses as Subject Complements
The fifth grammatical form that can perform the grammatical function of subject complement is the noun clause. Noun clauses are defined as subordinate clauses that consist of a clause preceded by a subordinating conjunction. For example, the following italicized noun clauses function as subject complements:
- The problem is that you think grammar is difficult to learn.
- My concern is what many students think about grammar.
- Your guest can be whomever you want to bring.
The five grammatical forms that can function as the subject complement in the English language are noun phrases, adjective phrases, prepositional phrases, verb phrases, and noun clauses. Both native speakers and ESL students must learn and understand the five grammatical forms to properly and fully construct sentences with subject complements in both spoken and written English.
Sources
Huddleston, Rodney. Introduction to the Grammar of English. Cambridge University Press: Cambridge, 1984.
Kosur, Heather Marie. "Lesson Plan: How to Teach ESL Students the Difference between Subject Complements and Direct Objects." Bright Hub. 14 May. 2009. Bright Hub. 21 May. 2009.
O'Dwyer, Bernard. Modern English Structures: Form, Function, and Position. Peterborough, Ontario: Broadview Press, 2000.
"Predicates, Objects, Complements." Guide to Grammar and Writing. Capital Community College Foundation. 29 Apr. 2009.
Heather Marie Kosur - About Me I earned a BA in English studies with a minor in creative writing from Illinois State University in May 2007 and an MS in ...
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