Avoid incomplete sentences. A sentence expresses a complete thought and includes a subject and a predicate. Avoid run-on sentences. Make the subject in your sentence agree in number with the verb in your sentence. If your verb is singular, you should use a singular subject.
Plural verbs require plural subjects.
Use singular pronouns to refer to singular antecedents, plural pronouns to refer to plural antecedents, and make your pronouns refer to a definite antecedent. In addition to the above, other errors may affect student grades. For example, in this class grades will be lowered when excessive spelling errors are made on outside assignments.