29 Common Grammatical Errors

Grammar

Many students self-diagnose themselves as “bad” writers because they don’t understand grammar. To some, grammar seems an impenetrable maze of rules and exceptions to those rules. However, grammar isn’t as intimidating if you can remember several important points. The first thing to remember is that you’re fluent in the language and use the rules correctly every day, and if English isn’t your first language, then you’ve mastered more than one grammar. When you have conversations, make online comments, or send a text, you’re using the language. It’s also important to realize that “grammar” is the word we use to describe the rules of a language—you learn the rules of your native language and internalize them at an early age. You’re already a grammatical expert as you can communicate with other speakers of your native language.
So why do so many people struggle with grammar? The answer is simple: experience. Students who struggle with grammar often don’t have enough experience reading and writing. After all, grammar is a system of rules that governs a language. We experience those rules when we read, and we practice following those rules when we write. Students may “study” the rules in school, but they don’t practice them enough through reading and writing. As your education progresses, you will practice reading and writing, improving your language skills.
Native English speakers tend to make the same kinds of mistakes in their formal writing. Below, you’ll find descriptions and advice for how to avoid making these mistakes. You should also note that these errors tend to revolve around punctuation, as we don’t punctuate our speech.

Sentence Errors

There are three common sentence errors we find in student writing: fragments, run-on sentences, and comma splices. Most instructors consider these errors serious, so you should know what they are and how to fix them.

Sentence Fragments

To understand sentence fragments, you need to know understand clauses. A clause is a group of words with a noun and a verb, forming a subject and predicate. Clauses can be independent or dependent. An independent clause is what we call a complete sentence; it doesn’t need any other structures. A dependent clause is not complete; it must be attached to an independent clause for the sentence to be complete. Sentence fragments are incomplete sentences. Because there are many grammatical structures with subjects and predicates that are dependent clauses, most of the sentence fragments in student writing tend to be dependent clauses.
You don’t necessarily need to memorize all the types of dependent clauses and their names. You just need to recognize the potential for fragments. If you’re unsure, you can check most sentences by reading the phrase “Is it true that” and finishing with the questionable sentence. A complete sentence will sound complete and a fragment will sound incomplete.

Sample Sentence Fragments

The second clause in each of these pairs is a fragment.
Steve couldn’t focus in his math class. Because he studied all night for his chemistry test.
(Is it true that because he studied all night for his chemistry test? If you read this, you can feel that something is missing)
The easy fix is to combine the two clauses:
Steve couldn’t focus in his math class because he studied all night for his chemistry test.
College students have many responsibilities. Which is why they should carefully manage their time.
This can be fixed in several ways:
College students have many responsibilities, so they should carefully manage their time.
Or
Because of their many responsibilities, college students should carefully manage their time.
Holly purchased her computer from an online shop. Having found the price reasonable.
Again, the easy fix is to combine the clauses:
Holly purchased her computer from an online shop, having found the price reasonable.
Sometimes long phrases are sources of fragments:
College students have many responsibilities. Such as homework, jobs, social life, and career planning.
Combine to fix:
College students have many responsibilities, such as homework, jobs, social life, and career planning.

 

Run-on Sentences and Comma Splices

These two errors are similar: both occur when a writer connects two sentences. When a writer connects two sentences with no punctuation, the error is called a run-on sentence. If the writer connects two sentences with a comma, the error is called a comma splice. Usually the writer’s instinct is to connect the sentences because they’re closely related and are often short

Examples of Run-ons and Comma Splices

Run-on:
We needed milk and supplies for this week’s lunches we went to the grocery store.
Or a comma splice:
We needed milk and supplies for this week’s lunches, we went to the grocery store.
There are two easy methods to fix run-on sentences or comma splices. The first method is to use a semicolon to connect the two sentences:
Run-on:
Megan earned a B in her organic chemistry class Eddie earned a B-.
Correct:
Megan earned a B in her organic chemistry class; Eddie earned a B-.
The second method is to separate the two clauses into separate sentences:
Correct:
Megan earned a B in her organic chemistry class. Eddie earned a B-.
Comma splice:
Last night, Selena worked late at the restaurant and then finished her calculus problems, she’s not going to tonight’s game.
Correct:
Last night, Selena worked late at the restaurant and then finished her calculus problems. She’s not going to tonight’s game.
or
Last night, Selena worked late at the restaurant and then finisher her calculus problems; she’s not going to tonight’s game.
Which method should you use? Either method is appropriate; however, a good general rule is to consider the length of the two sentences and the sentences around them. If the two sentences are short and closely related, a semicolon may be a better choice. If the surrounding sentences are mostly short, a semicolon may be a better choice. If one, or both, of the sentences are longer in length, or if they are surrounded by longer sentences, it may be more appropriate to separate them. Ultimately, the choice is yours.

 

There are some other methods for correcting comma splices and run-on sentences. For example, you may connect sentences with a comma if you also use a conjunction. Remember the acronym FANBOYS (For, And, Nor, But, Or, Yet, So) as it lists the conjunctions you may use.
We needed milk and supplies for this week’s lunches, so we went to the grocery store.
You can also make one of the sentences a dependent clause to fix comma splices or run-ons (you may need to add punctuation in the case of a run-on):
Because we needed milk and supplies for this week’s lunches, we went to the grocery store.
Megan earned a B in her organic chemistry class, while Eddie earned a B-.
Commas

Many students report that they don’t understand comma use. As a result, they tend to overuse or underuse commas. Sometimes, students will use commas to add a pause to a sentence, or they’ll add a comma where they would pause if reading the sentence aloud. This often leads to incorrect comma use, as commas are used to separate specific structures in sentences and not to add pauses.

Commas are used in many ways, but here are some common uses to remember.

Commas are used to separate three or more items in a series or a list:
  • We brought chips, ice, and sandwiches to the picnic.
  • During the semester, college students complete homework assignments, study for tests, and socialize with friends.

Some writers, and teachers, don’t use the comma before the conjunction; this comma is called the serial comma. While people disagree, there is no firm rule.

Commas are used to separate opening words, phrases, and clauses in a sentence:

  • Before we leave for our trip, we will check our packing list.
  • Jill, please submit your paper by this afternoon.
  • As we had several assignments to finish, we left the party early.
Commas are used for phrases or clauses that modify a noun when those phrases aren’t essential. By “essential,” we mean that the phrases or clauses define or restrict the meaning of a word:
  • The faculty, curious about the budget cuts, attended the meeting.
  • The faculty who were just hired attended the campus orientation meeting. (The clause “who were just hired” limits the meaning of “faculty” so no commas are required.)
Commas are used to introduce quotations:
  • Aristotle said, “The roots of education are bitter, but the fruit is sweet.”
  • “The roots of education are bitter,” Aristotle said, “but the fruit is sweet.”

 

Possessives and Plurals

Another common error students make is punctuating possessives and plurals. Most nouns use an -s to signal they’re plural; no punctuation is required. Possessive forms are used to show ownership and require an apostrophe -s as a sign. Students may know the difference but mistakenly use the incorrect punctuation. These errors may or may not show up in spell/grammar check software.

Possessives and Plurals

Singular Possessives:
  • Gillian’s purse
  • The dog’s collar
  • The student’s excuse
For most plural possessives just add an apostrophe:
  • The students’ excuses
  • The dogs’ collars

A common exception that confuses students is the word “it.”

  • It’s = contraction of “it is”
  • Its = possessive it

 

Common Spelling Typos

Many student papers will have spelling errors. Often, these errors are missed by spell check programs, or sometimes, students will forget to use spell check programs. The most common of these errors are homophones, which are words that sound the same but have different spellings and meanings. Remember to check your writing for these errors, especially if you know that you’ve made these errors in the past.

Common Typos

There, their, and they’re:
  • There—adverb: The book is over there.
  • Their—possessive of they: They store their books in the other room.
  • They’re—contraction of they are: They’re attending the lecture next week.
Your and you’re
  • Your—possessive of you: Your order arrived yesterday.
  • You’re—contraction of you are: You’re studying for tomorrow’s test?
Loose and Lose
  • Loose—not secure, not tight: The fan rattled because of a loose screw.
  • Lose—misplace, not win: Sam didn’t want to lose the bet.
One easy way to look for these errors is to us the ctrl+F function on your computer. This function will search for specific words. If you know that you frequently misuse “you” and “you’re,” then you can search for each to ensure that you’re using them correctly.

 

Active and Passive Voice:

 

 

 

 

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Writing and Rhetoric by Heather Hopkins Bowers, Anthony Ruggiero, and Jason Saphara is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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