30 rules of subject-verb agreement and their example
•A VERB MUST ACCEPT IT'S SUBJECT IN QUALITY
•WHEN THE SUBJECT IS A MIXTURE OF TWO OR MORE PRONOUNS AND NOUNS HELD TOGETHER BY "AND" IT MUST BE ACCEPTED BY THE VERB.
•A SINGULAR VERB IS REQUIRED BY TWO SINGULAR VERB LING TOGETHER WITH "OR" OR "NOR".
•THE VERB SHOULD BE IN SINGULAR FORM FROM THE SUBJECT IS MADE BY CONJUNCTIONS LIKE "WITH", "AS WILL AS" ETC.
•SOMS WORDS LIKE "ENVY, NEITHER, EVERYONE, MANY, ETC" NEED ONLY SINGULAR VERBS.
•WHEN TWO SUBJECTS , LINKED BY "OR" OR "NOR",
THE VERB ACCEPTS THE SUBJECT THAT IS NEAR TO VERB.
This is my answer, Hope this helps