Subject - Verb Agreement relates to number agreement (singular or plural) between the subject and the verb that follows it. E.g.
A conjunction is a word which merely joins together sentences or clauses, and sometimes words.
An adjective is a word used with a noun ( or a pronoun) to add something for its meaning. The adjective may be used
A Verb is a word that tells or asserts something about a person or thing. It tells about the person or thing in the state of (a) doing, (b) being or (c) being acted up on. Thus a verb is a doing or being word.
A pronoun is used in place of a noun or nouns.