Agreement is the determination of the inflectional form of one word according to a grammatical feature, such as number or gender, of another word.
A collective noun used as subject is treated as singular when referring to the group as a unit:
A collective noun is treated as plural when referring to individual members of the group:
Words ending in '-ics' that refer to a body of knowledge, a science, or an art are usually considered singular.
Words ending in -ics that refer to qualities or physical qualities are usually considered plural:
Words such as 'politics', 'acoustics', and 'ethics' can be either singular or plural, according to the sense intended.
Be careful not to have a verb agree with an expression that is not the subject of the verb. The subjects and the verbs are highlighted the following sentences: