An intransitive verb does not have an object. However, it manages to express a complete thought without the help of other words.
Look at the following sentences.
- Fire burns.
- The wind blows.
- Birds fly.
Here the intransitive verbs burns, blows and fly express a complete thought. Hence they are called verbs of complete predication.
Now study the following sentences.
- The girl seemed ….
- The dog is …
Both the verbs italicized are verbs of incomplete predication because they do not express a complete thought. Some word or words have to be supplied to complete their sense.
The girl seemed excited.
The dog is hungry.
The words thus added to complete the meaning of a verb of incomplete predication are called its complement.
The complement of the intransitive verb always describes the subject and hence it is called the subject complement.
The common verbs of incomplete predication are: be (is, am, are, was, were), seem, appear, look, become, feel and grow.
- The night grew dark.
- She looked innocent.
- Alice is a cardiologist.
- Mosquitoes appear everywhere.
- He became a millionaire.
- I feel tired.
The complement of a verb of incomplete predication can be a noun, an adjective, a pronoun, a present participle, a to-infinitive or an adverb.