Subject Complement

Read the sentences given below:

The birds fly.
The wind blows.
The moon shines.
Here the verbs fly, blows and shines are intransitive because they do not have objects. Still they express a complete thought without the help of any other words. Hence, they are called verbs of complete predication.

Now read the sentences given below:

The boy seemed …
The dog is …

Here the verbs seemed and is do not express a complete thought. They are, therefore, called verbs of incomplete predication. These verbs require some word or words to complete their sense.

The boy seemed upset.
The dog is hungry.

The fragment ‘The boy seemed’ turns into a complete sentence when the adjective upset is added to it. Similarly, the fragment ‘The dog is’ changes into a complete sentence when the adjective hungry is added to it. The words thus added to complete the meaning of the verb are called its complement.

The complement of the intransitive verb always describes the subject and is therefore called the subject complement.

The most common verb of incomplete predication is be (is, am, are, was and were). Others are seem, appear, look, become, feel, grow etc.

John is a good painter.
The painting looked beautiful.
Alice seemed anxious.
The mosquitoes appear everywhere.
The children are playing.
This house is to let.

The subject complement may be a noun, a pronoun, an adjective, a participle, a to-infinitive or an adverb.

Object complement

Read the sentences given below:

They appointed Harry Chairman.

In the sentence given above, Harry is the object of the transitive verb appointed. But if you say ‘They appointed Harry’, the sense is incomplete. In addition to the object Harry, we need another word to complete the sense. The word Chairman which completes the meaning of the sentence is called its complement. Since it refers to the object it is called the object complement.

More examples are given below:

The jury found him innocent.

Here the adjective innocent completes the meaning of the sentence by saying something about the object him. It is therefore called the complement of the object him.

The captain’s death forced the soldiers to surrender.

Here the to-infinitive to surrender completes the meaning of the sentence by saying something about the object soldiers. To surrender is therefore the complement of the object soldiers.

The object complement may be an adjective, a noun, a participle, an infinitive or a phrase.