What is subject, verb anf agreement

Subject - the one that is doing the following action.

Verb-describes the action made by the subject.

Agreement-accordance in opinions or feelings.

Explanation:It explains the way you should use different forms of verbs for different kinds of subjects. For example when you use the subject 'john' with a verb like 'talk' you should add s at the end of the verb for present simple tense or when you use anybody as an subject you must use a verb with s or es at the end of it. This is called subject and verb agreement.

There are lots of different subjects and different verbs form you should use with each other. For more information you can refer to Betty Azar grammar book (Blue cover) and look for 'Subject and Verb Agreement section'.