Grammar Mistakes You Should Avoid

Mistake 1: Using whom as a subject
INCORRECT: Fire personnel radioed deputies to stop the driver, whom, according to reports, appeared to have been under the influence of intoxicants.
CORRECT : Fire personnel radioed deputies to stop the driver, who, according to reports, appeared to have been under the influence of intoxicants.
In this sentence, the pronoun is the subject of the verb appeared and therefore requires the subject form who. The object form of who is whom, which functions as the object of a verb or as the object of a preposition:
That is the man whom I saw at the window. (object of the verb saw)
Did he say to whom he sent the letter? (object of the preposition to)
The misuse of whom as a subject frequently occurs when a phrase intervenes between the pronoun and its subject. Be especially careful with such expressions as “according to so-and-so,” “in my opinion,” “one suspects,” etc. Less frequently, but more embarrassingly, whom is sometimes substituted for who when little or nothing stands between it and its verb, as in this sentence taken from a news account: “An off-duty fireman whom lives in the area provided immediate assistance.”

Mistake 2: Unnecessary would in a wish about the past
INCORRECT: Ten Things I Wish I Would Have Known When I Was Twenty
CORRECT : Ten Things I Wish I Had Known When I Was Twenty
The opportunity for knowing the ten things existed in the past, but exists no longer. The tense required, therefore, is the past perfect (had + past participle).

Mistake 3: Dangling modifier
INCORRECT: At the age of four, Sam’s family moved from Florida, Missouri, to Hannibal.
CORRECT : At the age of four, Sam moved with his family from Florida, Missouri, to Hannibal.
Modifiers should be positioned as closely as possible to the element they modify. The modifying phrase “At the age of four” modifies “Sam,” not “Sam’s family.”

Mistake 4: Subject-Verb disagreement with delayed subject
INCORRECT: There goes Sally and Greg on their way to the movies.
CORRECT : There go Sally and Greg on their way to the movies.
Subjects and verbs must agree in number. When a sentence begins with here or there, the true subject of the sentence follows the verb. “Sally and Greg” is a plural subject, so the verb go must also be plural: “Sally and Greg go.”

Mistake 5: Incorrect use of object pronouns
INCORRECT: Me and my brothers all have college degrees in business.
CORRECT : My brothers and I all have college degrees in business.
Several English pronouns retain different forms that indicate their function in a sentence. Me is an object form. In the example, it is incorrectly used as the subject of the verb have. Other object forms often used incorrectly are him, her, us, them, and whom.