4 common grammar mistakes and how to fix them

Even before I became a high school English teacher, I felt passionately about correct grammar. Strangely enough, I never received strong formal grammar instruction in school because when you were in the advanced English classes, the emphasis was on reading, critical thinking, and writing.

As any avid readers can relate, grammar and vocabulary comes more naturally the more you read because you internalize the rules and words in practical action. I think grammar and vocabulary are actually more effective this way. Although, admittedly, I do not know all the grammar rules and crazy nuances that come with our wonderful English language, I actually do not think they are all that important.


Did the English teacher really just say that? Yes, I sure did. Let me explain though. I value being able to write and speak compelling arguments. How compelling will your argument be if you have incorrect spelling, poor grammar, and limited vocabulary? Not very, you guessed it.

4 common grammar mistakes (and how to fix them).

So before I was a teacher, while I may not have been able to explain how I knew correct grammar, I still knew it, and to me, that is what is important. Because of that, I think a practical application approach to teaching vocabulary and grammar, through lots of guided reading and discussion, is more effective than expecting students to memorize rules in isolated exercises. Anyway, I digress: The purpose of this post is to share four common grammatical errors I commonly see and hear and share how to fix them.

1. This is she (not this is her!).

Ring, ring.

Hi, is Lindsay there?

Yes this is…

Would you say ‘her’ instead of ‘she’? If so, I’m sorry to say, you would be incorrect. When you are asked about your identity, which commonly occurs on the phone, please ingrain this rule in your brain now, as my mom did since I was a child. It’s not too late for you! If you’ve been doing this wrong your whole life, it may feel funny, but that is not a reason to speak incorrectly. Will it help you to know the reasoning behind it? Okay, here it is put simply:

Why ‘this is she/he’?

Let’s break down the statement, ‘This is she.’

  • This is your subject and is is your verb – not just any verb, a linking verb. Linking verbs connect two of the same parts of speech.
  • Since we know ‘this’ is a subject, we know that whatever comes after ‘is’ must also be a subject.
  • She and her are both pronouns but serve different functions. She acts as a nominative pronoun, which just means it stands as a subject, while her is an objective pronoun, meaning it acts as an object.
  • Since linking verbs connect two like grammatical units, it must be ‘this is she.’
  • My mom taught this to my siblings and me as soon as we could answer the phone!

Another way to think about it is by rearranging the sentence to see what makes sense.

Hi, may I speak to Lindsay?

This is her–> Her is Lindsay. Mmmm, nope. Doesn’t work.

This is she–> She is Lindsay. Yup, bingo!

2. Who and Whom

Before I knew the rules for when to use who and whom in grammar school, I always just thought ‘whom’ sounded fancy and sophisticated and right. But nothing is less fancy and unsophisticated than using the wrong word and believing you’re right. Luckily, this is an easy one. Think of this:

Who = she, he

Whom = her, him

Now try filling in the blank to see which is correct.

______ likes Taylor Swift’s new album? (‘Her likes it’ sounds wrong, so it must be ‘who.)

To _____ did you give her album to for Christmas? (I gave it to he? Nope. I gave it to him, so use whom.)

Grammar errors- It's Simply Lindsay

3. Commas and conjunctions

For some reason, people really struggle with commas. People are either comma happy or comma shy; rarely are commas used correctly. Sure, many comma rules are ambiguous, but one rule is completely clear – commas with conjunctions.

A conjunction is a little word that connects other words, phrases, or clauses (for, and, nor, but, or, yet, so). When you see a conjunction in a sentence, do you put a comma before it? It depends on what comes before and after the conjunction.

Use a comma when the conjunction combines two complete sentences (also called independent clauses). You can simply cover up the conjunction and the rest of the sentence to isolate both parts to determine if you have complete sentences that could stand alone.

Example: I want to leave the house, but I have too much work to do.

Look at the two underlined parts; are they complete sentences? Can they stand alone? Yes. They are two complete sentences on their own, combined with the conjuction but, so per the rule, we put a comma.

If only the first part before the conjunction is a complete sentence and the second one is not, do not use a comma (or vice versa).

Example: I want to leave the house and go to the store.

I see a conjunction (and), but do we need a comma? Cover up “and go to the store.” That leaves us with “I want to leave the house.” Is that a complete sentence? Yes. Now do the other part of the sentence. Is “go to the store” a complete sentence? Nope, so no comma needed.

Grammar- It's Simply Lindsay

4. Punctuation with Parentheses

Do you know how to punctuate your end marks with parentheses? Is there a difference when the parentheses are located in the middle or at the end of a sentence? (No.) Is there a difference with the parentheses stand alone? (Yes.)

Parentheses in the middle of a sentence

Do not capitalize words in your parentheses when they come in the middle of the sentence (unless of course they are proper nouns). Do not use end punctuation; this will only come at the end of the sentence.

Parentheses at the end of a sentence

The same rules apply as above. There is no end punctuation until the end of the sentence, which means after the last parentheses mark, not inside the mark.

Incorrect: I’m ravenous and thinking about having a bowl of cereal (even though I already had dinner.).

This is incorrect because there is a period inside and outside the parentheses.

Parentheses standing alone

When your parentheses are not included as part of another sentence and instead stand alone, treat it like a normal sentence, which means your end mark goes at the end of the sentence, or inside the parentheses.

(This is what I’m talking about.)

(The period is inside the parentheses, not outside, and not inside and outside.)


If the words inside the parentheses have a question mark or exclamation mark, you will include that inside the marks, and keep your period outside the parentheses as well.

I stayed up way too late (even though my baby went to sleep early) and felt exhausted the next day (how silly was I?).

Since the last statement in my parentheses is a question, I put the question mark inside and the end punctuation of a period outside.

Whoever you are – students, writers, bloggers, working professionals, moms, dads, grandparents, musicians, artists – I hope you take these four common grammatical errors to heart (and mind), and please make the world a better place by correcting these faux pas. You will make yourself look and sound more credible, and now you know the reasoning behind these rules.

Common grammar errors- It's Simply Lindsay

Did you know and understand the reasoning behind all of these rules? Do any grammar mistakes really bother you, too?

PS- Coming soon, a grammar post of my personal preferences of certain ‘rules’ – how exciting, I know!!

  • Jackie

    This post will help me get through writing papers in college 🙂 thank you

    • Lindsay Katherine

      Hooray!! Oh so many more (hopefully) helpful grammar tips forthcoming.

  • YES YES YES! I had so many of my students struggle with these; especially the commas. My kids were SO comma happy, they would stick them EVERYWHERE. We had a nice week long unit dedicated to just commas in the middle of my creative writing class because I couldn’t stand it any more!

    • Lindsay Katherine

      I SO wish we lived near each other so we could get together and discuss all the wonderful things we’re passionate about!!

  • This is great!!!! I love this. Thank you! 🙂

    • Lindsay Katherine

      Hope it comes in handy : )

  • Yamini Tiwari

    Thanks for sharing this post. Will surely help a lot of bloggers and students. Great work.

    • Lindsay Katherine

      Well thanks for reading Yamini – I hope it helps even one person!

  • Whew! Glad to know my English teachers did a good job and that I haven’t forgotten their lessons. Good stuff here. Thanks!

    • Lindsay Katherine

      Hooray!! That makes me so happy. If you have a way of contacting any of them, I’m sure they’d love to hear from you!

  • Becky @Disney in your Day

    Great tips – I’m a librarian but was previously an English teacher. My husband got me a t-shirt that says “Warning: I am silently correcting your grammar”!

    • Lindsay Katherine

      Oh my gosh, I didn’t know you used to be an English teacher! I knew I liked you from the beginning : ) Now I like you ever more that you’re also a librarian now. I love that shirt your husband got you, too funny.

  • That’s a really great grammar lesson! Many people get confused between who and whom but this trick clears it up! 🙂

    • Lindsay Katherine

      Well I hope this little who/whom trick helps!

  • I dislike exception of any kind when it comes to grammar. That is what kills me at the end. I really liked the quick lesson. I needed the comma reminded! Thanks!

    • Lindsay Katherine

      The English language is the most confusing – all other languages are very cut and dry, so I’ve heard learning English over any other language is the more difficult!

  • Autumn Dickens

    Thanks so much for the mini lesson. You made it so clear and concise. Grammar can definitely be tricky.

    • Lindsay Katherine

      I’m glad you found it understandable!

  • I’m a self-proclaimed grammar nerd. I’ve been thinking about doing a monthly grammar post. My biggest pet peeve is there/their/they’re. I understand why people don’t know the difference, but they’re also SO different that I think people should know!

    • Lindsay Katherine

      I love that you’re a grammar nerd! Yayyyy. You’re more forgiving than I am though – I don’t understand why people do not know the forms of there.

      • I’m so bad though, because I totally judge people on their grammar! But it really does make a difference in your intelligence!!!

  • Rae

    I have no conscious memory of having those rules installed—but they are there, as are several others (I versus me, for example).
    My grammar-Nazi mother swears sentence diagramming helps construct proper sentences. She is also obsessive about Associated Press-style writing and comma usage is slightly different using those rules.

    • Lindsay Katherine

      Ahhh did your mom make you diagram sentences?? Is she a journalist, since she’s into Associated Press? Thanks for reading, Rae!

  • Shann Eva

    I always thought the punctuation went inside the parentheses. Thanks for the lesson.

    • Lindsay Katherine

      Glad you learned something new!

  • As a language teacher, I love this 🙂 I’m always amazed by how little my students know about all this! The comma one is helpful for me because I feel like I mix that rule up sometimes. Thanks for breaking it all down!

    • Lindsay Katherine

      I’m glad you can relate! It’s not only students though; I’ve seen these errors in all different professional environments too.

  • I have to admit grammar is not my strong suit. Thankfully, I have a husband who is a good editor and catches my mistakes!

    • Lindsay Katherine

      It’s hard to edit your own work! You spend so much time brainstorming, writing, reading it, reading it again…your brain gets used to the words and it’s hard to catch mistakes. Something I do, and encourage my students to do, is read your writing out loud. It’s easier to catch mistakes that way : )

  • Serene Mom

    I love writing, and I’m decent with grammar, but I loved these tips. Especially about the usage of ‘who’ and ‘whom’ it’s always bugged me lol.

    • Lindsay Katherine

      Of course you love writing! You’re a fabulous writer.

  • Hooray for grammar! My mom’s ex-boyfriend bought me The Grammar Bible for Christmas when I was in my early teens. Will your be doing a post on “definitely” vs “defiantly”? Because I would defiantly read that one (haha)!

    • Lindsay Katherine

      Hahah, well since you will defiantly read that post, then I must read it : ) That’s hilarious that you received that as a Christmas present – I love it. My daughter will certainly get that one day.

  • I’ve never seen who and whom explained so simply. Now I can use it without sounding pompous. 🙂

    • Lindsay Katherine

      I’m glad you found this rule so simple! I don’t know why it isn’t explained that way from the start. Now you can whom away confidently.

  • I love your simple and easy to understand explanations. While I’m not a grammar Nazi or anything, I’m a grammar nerd. I’ve read grammar and writing books cover to cover for fun. Rarely have I found a book that explained these concepts so succinctly. Your students are lucky to have a teacher like you!

    • Lindsay Katherine

      Wow Kelsey, you just made my day! Reading grammar and writing books for fun? A girl after my own heart : )

  • I’m definitely saving the who/whom image!

    • Lindsay Katherine

      Oh good! Hope it helped : )

  • Anamika Ojha

    Nice grammar lessons!

    • Lindsay Katherine

      Thanks for reading.

  • Great Post! This is quite helpful especially as english is my second language. I like also the parentheses tips as I always wonder if the punctuation of the sentence needed to be inside the parenthese or not. Thanks for sharing!

    • Lindsay Katherine

      I’m so glad you found this helpful. What is your native language? I have heard that English is the most challenging language to learn because of all of the crazy rules and exceptions.

  • Dana Brillante-Peller

    I totally mess up and commas and semi colons all the time!

    • Lindsay Katherine

      You totally USED to mess them up all the time : ) Now you know the difference!

  • This is actually super helpful, as embarrassing as that is to admit :). Thank you and pinning (no comma in this sentence right?). Lol

    • Lindsay Katherine

      No embarrassment! I see professionals, even writers, make these mistakes ALL the time. And yes, you did the no comma correctly : )

  • OMG Linday, can you please just do a Grammar series like every week, love how simple and sensible your explanations are!! I always struggle with who and Whom, have caught myself using them interchangeably sometimes but not anymore, thanks to you! Your students are sooooo lucky 🙂
    xx, Kusum | http://www.sveeteskapes.com

    • Lindsay Katherine

      You just made my day!! I’m so glad this is easy and useful for you. I will definitely do more grammar posts; do you have any topics in particular you’d like me to cover so I make sure I get them?

  • Patie Nduta

    Wow, awesome. Haha, I break rule 1 and 3 more often than not.