1) a verb must agree to its subject by number (adding -s to the end of the verb if singular) 2) "you" is always plural 3) Intervening expressions do not affect the verb. Example: My mother, along with her friends, AGREES with my take on the subject. 4) plural sounding singular nouns are singular. Example: Mathematics IS a very hard subject. 5) If there is a fraction, then refer to the "Of-phrase" Example: One third OF THE PIES ARE gone. Another example: on fourth OF THE BOOK IS boring.