The most common grammar mistake has to do with the ability to count. Fortunately, you only have to be able to count more than 1.

If I write “A man buys a house”, he can count the number of men: 1.

If I write “Men buy houses,” it must count more than 1 because this sentence describes more than 1 man.

Now, let’s take a closer look at these two examples.

In the first sentence, “A man buys a house”, the subject is 1 man, described as “a man”. The verb “buy” ends with the letter “s”. When we conjugate verbs in the present tense, we can see that third person singular verbs end with the letter “s”.

First person, singular subject: “I buy.”

Second person, singular subject: “You buy.”

Third person, singular subject: “Buy”. (Notice the “s” at the end of the verb).

What we have just learned is that if the subject is singular, the verb is also singular, that is, only a person or thing. Also, we see that the verb has an “s”.

In the second sentence, “Men buy houses”, we have more than 1 man, described as “men”. The subject is plural (more than 1) and the verb no longer has the “s”.

And this is where we get the most common grammatical mistake. The most common grammatical mistake is to use a singular subject (a person or thing) with a third person singular verb (the verb has the “s”) but then refer to the subject with a plural pronoun.

Maybe an example will help here. Let’s build a sentence part by part and see what is happening.

Start of wrong sentence: “All”: this is 1 person because it refers to each individual person, so it is singular.

Continuation of the incorrect sentence: “Everyone needs” – We add the verb in the third person singular, which has an “s”.

Ending wrong sentence: “spend your money wisely”. -The pronoun in this part is “su” and refers to the subject, “Todos”. “Su” is a plural subject, which means that it refers to more than 1 person.

Here is the complete sentence with the grammatical error: “Everyone should spend their money wisely.” This sentence has a singular subject, a singular verb, and a plural pronoun. The problem is the pronoun.

For correct grammar, the pronoun must be plural or singular depending on the word to which it refers. If it refers to a singular person or thing, it must be singular. If it refers to more than one person or thing, it must also be plural.

The correct pronouns that can refer to “everyone” in this sample are “his”, “she”, “his” and “whose”. These are all singular pronouns because they refer to a person or thing.

This morning, I was reading one of my favorite blogs, The Motley Fool, and I came across this phrase: “Third, for someone who wants to maximize their time …” (http://www.fool.com/investing / general / 2014 /01/05/should-you-start-buying-stocks-in-2014-heres-what.aspx). Wow, it contains the most common grammar mistake.

The faulty sentence contains a singular subject, “who.” We know that “who” is singular because it refers to “someone”, which is singular. We also know that it is singular because it has a singular verb: “wants”. The verb ends in “s”, so it is third person singular.

Therefore, the sentence has a singular subject and a singular verb. Then we see the pronoun “su”. The pronoun is not singular; refers to more than 1 person. And this is the most common grammar mistake.

To refer to the singular subject, the pronoun must also be singular. If we only change the pronoun to correct this sentence, we get these options.

“Third, for someone who wants to maximize their time …” (This is correct, but some people think that using “su” is sexist, so this is not a good option).

“Third, for someone who wants to maximize their time …” (The same problem as the previous correction).

“Third, for someone who wants to maximize their time …” (This doesn’t make sense. We don’t use “su” to refer to people).

“Third, for someone who wants to maximize whose time …” (This doesn’t make sense either).

Then, what are we going to do? Correcting the grammar mistake is simple.

If we want to use a plural pronoun, we need to have a plural subject and verb. Therefore, we can change “someone” for “people” and change “wants” to “want”. Here is the correct sentence:

“Third, for people who want to make the most of their time …”

Now, the subject “who” is plural. We know that it is plural because it refers to “people”. “People” is plural because it describes more than one person. We also know that it is plural because its verb is “want”, which no longer contains the “s”.

A plural pronoun (“your”) can only refer to a plural subject (“who”) that has a plural verb (“want”). Now that we have a plural subject and a plural pronoun, the sentence is correct.

Here’s the tip: If you use a plural pronoun, such as “they,” “their,” and “they,” mark the word it refers to. If the pronoun refers to more than one thing, it is correct. If you refer to 1 thing, the pronoun is incorrect and you have made the most common grammatical mistake.

You can correct this error in two ways:

1. Make the pronoun singular (“Third, for someone who wants to make the most of their time …”) or

2. Change the word the pronoun refers to so that the pronoun refers to more than one thing (“Third, for people who want to make the most of their time …”)

The “Concise Technical and Academic Writing Guide” writing guide is a good source of information to help you understand and correct these and other common grammatical mistakes.