The trick to looking for subject-verb disagreements is to identify the verb in a single sentence. The verb in the sentence will help you find the subject that will tell you if you have the correct form of the verb. The verb is the easiest to identify as a word that can come right after the pronouns “me”, “you”, “you” and “That”. In cases where two words can match the sentence depending on the pronoun, the verb is the word that changes when you change the temporal form of the sentence. For example, in the sentence “The exhausted runner has crossed the finish line”, both “exhausted” and “crossed” could come after a pronoun. If we change the sentence from the past to the present, “The exhausted runner crosses the finish line”, we see that because “cross” has been modified to put the sentence in the contemporary form, it is the verb. To check this difficult aspect of English grammar, take a look at our article on the over-conformity of pronouns. There are countless grammatical rules in the English language. The singular noun in the subject requires the singular form of the verb (either first or third person), while plural nouns require the plural form of the verb. (A correct assessment of the error.) Verb form defects occur when you use the wrong verb. You are one of the most common grammar mistakes. The form of the verb tells the reader your sentences when the plot takes place – in the past, present or future.. .