The Complement can often be confused with the Object. While the Subject and Object of a clause, in the vast majority of cases, refer to different entities, the Complement gives more information about either the Subject or the Object. As with the Subject and Object elements, there is only one grouping or phrase which is considered to be the Complement of a clause.
Let's begin by looking at some pairs of sentences where this information centres on the Subject.
So, in the preceding examples the first sentence of each pair contains an Object - Harry, the load, the lamp post. These are clearly not the same entities as the Subjects of the sentences. However, the same cannot be said for the second sentence of each pair where there is a strong connection between the Subjects and the phrases a policeman, awful and what she wanted for her birthday. These phrases act to identify the Subject more precisely. These are known as Complements; more specifically they are subject complements because they define the Subjects of the clauses, in this case Bill, the camel and a car.
In most sentences where the Complement defines the Subject, you will find a particular type of verb being used. The most usual is the verb be and its forms (e.g. am, are, was, have been) followed by a noun phrase or an adjective phrase, often as a single word. In the instances above, a policeman is a noun phrase and awful is an adjective phrase. Other examples are:
In all of these cases, the phrases after is, was and were define the Subject. You should notice that, although two of the Complements in the first set of examples contain adjectives (great, very rare Siberian), these are still treated as noun phrases because the main words in the groups are themselves nouns (healer, tigers).
Earlier I commented that a particular type of verb is often used in clauses with a subject Complement and that verb is usually be. However, there is a small number of other verbs either closely connected with be or to do with sensing that frequently occur in this type of clause. A short list with examples might include:
Be type: seem, appear, become, turn out, grow, remain
Sense type: look, sound, feel, taste, smell (all followed by like with a noun)
There is still one type of subject Complement that we haven't looked at yet - this is the subordinate clause. The example from the original sentences is:
Here a car is the Subject, the Verb is was and the Complement defining the Subject is what she wanted for her birthday, which is a clause since it has its own Subject (she) and Verb (wanted). Other examples of clauses used as subject Complements are:
In all the instances in the previous section the Complement gave additional information about the Subject of the clause. Additional information can similarly be given about the Object. Look at the examples below:
Here, the phrases in bold are giving extra information about the Objects of the clauses which are him, me, the outlaw, him, it. The object Complement usually follows the Object of the clause as in all the examples above and the choice of verb is not so restricted as it is with the subject Complement clauses.