Complements

A complement is an obligatory element that completes the meaning of the subject or direct object (Od).. The two types of complement are subject complement and object complement. Complements are realized by noun-like or adjective-like elements:

That boy is my brother (noun phrase)

This course is rather difficult (adjective phrase)..

Cs describes or refers to the subject and they occur only after a linking verb, the most common of which is the is the be verb (used as a main verb).

Co describes or refers to the direct object (Od). Since Co completes the meaning of Od, the later must be present in the clause. the following example, the Od is that boy and the Co is a genius: James considersthat boy a genius.

We can differentiate between these complements by using:

1. Be-replacement test

This test can be used to check if the main verb is a linking verb. Once we have determined the main verb as a linking verb, we would also have located the Cs as it occurs only after a linking verb.

E.g. This room feels cold.

This room is cold. (using this test, feels is a linking verb hence cold is Cs)

2. Be- insertion test

By this test, it is possible for the be verb to be inserted between Od and Co (after the insertion the meaning should remain).

E.g. a) She painted the wall bright pink.

The wall is /was bright pink. (passes this test – wall = Od, bright pink = Co)

b) Sue made her brother very angry.

Sue is very angry. (incorrect-changes the meaning of the sentence)

Her brother is/was very angry. (passes be-insertion test; her brother = Od, very angry = Co)

Compiled and contributed by Wang Jia