In grammar, a complement is a word, phrase, or clause that is essential to complete the meaning of a given expression, particularly a verb, adjective, or noun. Unlike optional modifiers, complements are necessary elements that provide crucial information, often acting as arguments that complete the meaning of a predicate.
Understanding Complements
A complement is not merely an additional detail; it's a structural requirement without which the sentence or phrase would be incomplete or nonsensical. They "complete" the thought initiated by another word.
For instance, in the sentence "She is happy," "happy" is a complement that completes the meaning of the linking verb "is" and describes the subject "She." Without "happy," "She is" doesn't convey a complete thought.
Key Characteristics of Complements
- Necessity: They are required for the grammatical completeness and meaning of the expression they complement.
- Forms: Complements can take various forms, including:
- Single words: (e.g., nouns, adjectives)
- Phrases: (e.g., prepositional phrases, noun phrases)
- Clauses: (e.g., noun clauses)
- Arguments: Complements are frequently arguments, meaning they are the entities or concepts that a verb or other predicate "takes" to form a complete idea. For example, a transitive verb typically requires a direct object as an argument.
Types of Complements with Examples
Complements are categorized based on what they complete. Here are the most common types:
1. Subject Complements
A subject complement follows a linking verb (such as be, seem, become, feel, look, sound, taste, smell) and refers back to or describes the subject of the sentence. They can be:
- Predicate Nominatives (or Predicate Nouns): A noun or pronoun that renames or identifies the subject.
- Example: She is a doctor. (doctor = subject complement, renaming "She")
- Predicate Adjectives: An adjective that describes the subject.
- Example: He feels tired. (tired = subject complement, describing "He")
2. Object Complements
An object complement follows a direct object and completes its meaning, often by describing or renaming it. It typically appears after verbs like make, call, name, elect, consider, find, paint, declare.
- Example: They elected him president. (president = object complement, renaming "him")
- Example: She painted the wall blue. (blue = object complement, describing "the wall")
3. Verb Complements
These are elements that complete the meaning of a verb, often directly affected by or receiving the action of the verb. Common verb complements include:
- Direct Objects: The noun or pronoun that receives the action of a transitive verb.
- Example: He ate an apple. (an apple = direct object, completing "ate")
- Indirect Objects: The noun or pronoun for whom or to whom the action of the verb is performed.
- Example: She gave him a book. (him = indirect object; "a book" is the direct object)
4. Adjective Complements
An adjective complement is a phrase or clause that completes the meaning of an adjective. These often answer questions like "about what?" or "of what?"
- Example: I am happy to see you. (to see you = adjective complement, completing "happy")
- Example: She is afraid of heights. (of heights = adjective complement, completing "afraid")
5. Adverbial Complements
While many adverbial phrases are optional modifiers, some are essential to complete the meaning of certain verbs, especially those indicating location or direction.
- Example: He lives in New York. (in New York = essential adverbial complement, completing "lives" by indicating location)
- Example: They put the book on the table. (on the table = essential adverbial complement, completing "put")
Complements vs. Modifiers
It's crucial to distinguish complements from modifiers. While both add information, complements are necessary for the grammatical completeness and meaning of the expression they complement. Modifiers, such as adverbs or adjectives that are not predicate adjectives, merely add additional information and can often be removed without rendering the sentence grammatically incomplete or nonsensical.
For example, in "The tall man walked slowly," "tall" (an adjective modifying "man") and "slowly" (an adverb modifying "walked") are modifiers. The sentence still makes sense as "The man walked." However, in "She is a student," "a student" is a complement; "She is" is incomplete.
Understanding complements is fundamental to analyzing sentence structure and grasping how meaning is constructed in language.
