Grammar is an important part of language that helps us communicate clearly and effectively. However, many people struggle with proper grammar and make common mistakes in their writing and speaking. In this comprehensive guide, we will go over some of the most common grammar mistakes, explain why they are incorrect, and provide tips for how to avoid these errors. Proper grammar takes practice, but being aware of what to look out for can help you improve your language skills.

Subject-Verb Agreement

One of the most common grammar mistakes is subject-verb agreement. This refers to the need for the subject and verb to agree in number; that is, a singular subject needs a singular verb, and a plural subject needs a plural verb. For example:

• Incorrect: She walk to school every day.
• Correct: She walks to school every day.
• Incorrect: My friends likes to read books.
• Correct: My friends like to read books.

Some cases that often trip people up:

• Collective nouns like team, jury, class, and family can take a singular or plural verb depending on the meaning. For example, a sports team that acts as a unit can take a singular verb like "is" while a group of individuals like a jury may take a plural verb like "are."
• Indefinite pronouns like each, everyone, someone, no one, anything are always singular. For example: Everyone is here.
• The words there is and there are at the beginning of a sentence can help you determine the subject and choose the right verb form. For example: There are many candidates running in this year's election.

To fix subject-verb agreement errors, carefully identify your subjects and choose verbs that correspond to the number of the subject.

Pronoun-Antecedent Agreement

Pronouns are words that stand in place of nouns, and they must agree with the noun they refer back to, which is called the antecedent. The antecedent usually comes before the pronoun in a sentence. Common pronouns include I, me, he, she, it, you, they, and we. Examples of pronoun-antecedent agreement errors:

• Incorrect: Mary did not want to spend all her money, so she was frugal with it's use.
• Correct: Mary did not want to spend all her money, so she was frugal with its use. (The pronoun "its" refers back to "money" which is singular, not "it's" which means "it is.")
• Incorrect: The team lost most of their games this season.
• Correct: The team lost most of its games this season. (The pronoun "its" refers back to the singular noun "team.")
• Incorrect: The students have to complete their homework if they want to pass the class.
• Correct: The students have to complete their homework if they want to pass the class. (Here the pronoun "their" agrees with the plural antecedent "students.")

To avoid pronoun-antecedent agreement errors, pay close attention to the noun that the pronoun refers back to. Identify whether the antecedent is singular or plural, and choose a pronoun that matches.

Verb Tense Consistency

Shifting verb tenses randomly can make your writing confusing and disjointed. When you start talking about an event in one tense, keep using that tense unless there is a clear reason to change to another tense. For example:

• Incorrect: Yesterday Sarah walked to the store and buys some milk.
• Correct: Yesterday Sarah walked to the store and bought some milk.
• Incorrect: He has been playing tennis for years and now practicing 3 times a week.
• Correct: He has been playing tennis for years and now practices 3 times a week.

Some tips for maintaining consistent verb tense:

• Decide which tense you want to write in before you begin. Past tense for past events, present for current events, etc.
• When describing ongoing or repeated actions, use the present perfect continuous tense consistently, not the simple present. For example, has been going, have been working.
• Avoid unnecessarily switching between past, present, and future tenses. Only change tenses when you need to indicate a change in time frame.
• Keep your tense consistent across bullet points. Don't switch between past and present tense.

Proofread your writing with a focus on verb tense to catch any inconsistencies. Reading aloud can help.

Comma Splices and Run-on Sentences

Comma splices and run-on sentences occur when two independent clauses are incorrectly joined together in one sentence either with just a comma or with no punctuation at all. For example:

• Incorrect (comma splice): My car broke down on the way home, I had to take the bus.
• Incorrect (run-on): My car broke down on the way home I had to take the bus.

To fix a comma splice, you can:

• Separate the clauses into two different sentences: My car broke down on the way home. I had to take the bus.
• Add a coordinating conjunction like "and," "but," "so," "yet," "nor," or "for" after the comma: My car broke down on the way home, so I had to take the bus.
• Use a semicolon instead of a comma to connect the closely related clauses: My car broke down on the way home; I had to take the bus.

To fix a run-on sentence, add appropriate punctuation or coordinating conjunctions to separate the clauses:

• My car broke down on the way home, so I had to take the bus.
• My car broke down on the way home; I had to take the bus.

When writing, look out for sentences with two independent clauses and make sure they are properly separated to avoid comma splices and run-ons. Reading your work aloud and pausing at commas can help you spot potential errors.

Misplaced and Dangling Modifiers

A modifier describes or qualifies another part of a sentence but should be placed as close as possible to the word it modifies. If it's in the wrong place, it can create confusion or unintentionally modify the wrong word. For example:

• Misplaced: The coach critiqued the player with long blonde hair after the game. (Incorrectly implies the coach has blonde hair)
• Correct: The coach critiqued the player with long blonde hair after the game.
• Dangling: Riding her bike quickly, the tree branch hit Lucy in the face. (The modifier incorrectly refers to the tree branch)
• Correct: Riding her bike quickly, Lucy was hit in the face by a tree branch.

Some strategies to fix misplaced or dangling modifiers:

• Place modifiers right next to the noun or verb they describe: The player with long blonde hair was critiqued by the coach.
• Avoid starting a sentence with a participle or participial phrase unless you make the subject clear right away: Riding quickly, Lucy was hit by a tree branch as she rode her bike.
• If a modifier is at the beginning or end of a sentence, ensure it clearly refers to the right subject. Rearrange if needed.
• Read your writing carefully and identify any descriptive words or phrases. Check what each one is modifying.

Parallel Structure

When listing a series of verbs, nouns, phrases, or clauses, these items should follow parallel structure. This means using the same grammatical form for each element in the list or sentence. Non-parallel structure sounds awkward and sloppy. For example:

• Incorrect: Sarah likes running, swimming, and to ride her bike. (Verb, gerund, infinitive verb)
• Correct: Sarah likes running, swimming, and riding her bike. (all gerund verbs)
• Incorrect: The teacher said to bring pencils, paper, and that we wear sneakers. (Infinitive verb, noun, clause)
• Correct: The teacher said to bring pencils, paper, and sneakers. (All infinitive verbs)

Some tips for parallel structure:

• Identify any lists or comparisons in your writing. Check that each point is in the same grammatical form (noun to noun, gerund to gerund, etc).
• When linking two clauses with a coordinating conjunction like "and" or "but," make sure the same structure is used on both sides.
• For a series of verbs, keep them all in the same tense and voice (active/passive).
• Reading your writing out loud can help you notice any lack of parallelism. Listen for a consistent flow.
• When in doubt, simplify long lists by breaking them into separate sentences.

Mixed Constructions

In an effort to vary sentence structure, some writers will improperly mix different grammatical constructions in one sentence. This results in an awkward hybrid style. For example:

• Incorrect: The boss told the staff they would all be getting bonuses this year and that working on Saturdays was mandatory. (Combines an indirect statement with an independent clause)
• Correct: The boss told the staff that they would all be getting bonuses this year. Working on Saturdays was now mandatory.
• Incorrect: Lisa hoped to get an A on the test she studied all week and working harder than before. (Combines a clause with a verb and a participial phrase modifier)
• Correct: Lisa hoped to get an A on the test. She had studied all week and worked harder than before.

Some tips to avoid mixed constructions:

• Stick to one type of construction in each sentence unless you intentionally want to combine them for stylistic effect. Don't unintentionally switch between clauses, modifiers, statements, etc.
• Break up long sentences with mixed types of phrases and clauses into shorter, clearer sentences.
• When proofreading, look for any sentences that seem confusing or contain abrupt switches between grammatical structures. Separate into stand-alone sentences.
• Read sentences aloud to help spot awkward mixes of styles and catch confusing syntax.

Incorrect Pronoun Case

Pronouns have subjective, objective, and possessive forms. They must match their function in the sentence. Using the wrong pronoun case is a common mistake. For example:

• Incorrect: Sally and me went shopping at the mall. ("me" is the objective case)
• Correct: Sally and I went shopping at the mall. ("I" is the subjective case)
• Incorrect: Please give the package to Bob and I. ("I" is the subjective case)
• Correct: Please give the package to Bob and me. ("me" is the objective case)
• Incorrect: The trophy is shared between the coach and I. ("I" is the subjective case)
• Correct: The trophy is shared between the coach and me. ("me" is the objective case)

Some tips for proper pronoun case:

• I/me: Use I for subjects, me for objects. "She and I went to the store." vs "Thanks for inviting my friend and me."
• Who/whom: Who is for subjects, whom is for objects. "Who made this dish?" vs "To whom should I mail this?"
• He/him, she/her, they/them follow the same structure: "They want to interview her for the job." "I sent the email to him."
• Check cases after prepositions and conjunctions like and/but/to/for/with: "I made reservations for her and me."
• If in doubt, remove the other subject to test if your pronoun is correct: "They invited she" would clearly sound wrong without the "they."

Confusing Homophones

Homophones are words that sound the same but have different meanings and spellings. Some commonly confused homophones include:

• They're/their/there - They're is short for "they are." Their means belonging to them. There refers to a place.
• Its/it's - Its shows possession while it's is short for "it is."
• Your/you're - Your is possessive, you're is short for "you are."
• To/two/too - To is a preposition, two is the number, too means also.
• Would have/would of - Would have is correct while would of makes no sense logically.
• Could have/could of - Same as above: only "could have" is grammatically correct.
• Then/than - Then refers to time while than is used for comparisons.
• Whose/who's - Whose is possessive like “whose book is this?” Who's means “who is.”

To avoid confusing these words:

• If in doubt, plug in the words the contraction stands for, like "they are" or "it is" to test which option makes sense.
• Keep a list of commonly confused homophones and their meanings. Double-check the definitions when using these words.
• Read sentences aloud containing homophones to check which meaning would make logical sense.
• Check for incorrect homophones when proofreading writing. Pay extra attention when one option is a contraction.

Proper grammar allows us to communicate ideas clearly and precisely. However, many people continue to make the same common grammar mistakes in their writing and speaking. Applying the tips and strategies covered in this guide can help you identify and eliminate these errors in your work. With practice and patience, you can improve your grammar skills dramatically. Reference tools like dictionaries and online resources can supplement your learning. Just remember that even professional writers make grammar mistakes, so don’t get discouraged. Paying a little extra attention to things like subject-verb agreement, pronoun cases, and parallel structure can go a long way toward helping you polish your language use.