Intransitive verbs do not take an object. Examples are given below.
He sat on the floor.
The old man laughed.
Some intransitive verbs require a word or phrase to complete the predicate and make sense of the sentence. Such verbs are called verbs of incomplete predication. Examples are: is, am, are, was, were, become, look, seem, appear, taste, smell, grow, turn etc.
The earth is round.
Honey tastes sweet.
The milk turned sour.
He became a monk.
The night grew dark.
The word or words required to complete the predicate is called the complement of the verb. In the above sentence, the words round, sweet, sour, monk and dark are the complements of the verbs is, tastes, turned, became and grew respectively.
When the complement of a verb says something about the subject, it is called a subject complement.
Read the following sentence.
Susie is a writer.
Here the noun ‘writer’ is the complement of the verb ‘is’. As it says something about the subject Susie, it is a subject complement.
More examples are given below.
She is intelligent. (Subject complement – intelligent)
This house is to let. (Subject complement – to let)
The child continued crying. (Subject complement – crying)
She looked depressed. (Subject complement – depressed)
Transitive verbs have objects, but some transitive verbs require, besides their objects, some complements to complete their meaning.
The teacher appointed Charles monitor.
They elected Ram their president.
Frustration drove him mad.
They named her Angel.
Here the complements monitor, president, mad and Angel say something about the objects Charles, Ram, him and her. A complement which says something about the object is called an object complement.