Grammar Study Guide for the HESI Exam

Commonly Confused Words

English is an especially challenging language as there are so many words that sound the same but are spelled differently, or words that seem like they mean the same thing but have slightly different uses.

Some of these words are called homophones, words that sound exactly the same but are spelled or used differently. Other commonly confused pairs are simply misused because their meanings are so similar that it is easy to mix them up.

Affect/Effect

The confusion between affect and effect is one of the most common mistakes in English writing, probably because it is one of the trickiest rules to grasp!

Affect is an action, meaning it is a verb. Think of the phrase cause and effect—the cause is the affect.

I am not affected by the sun; I hardly ever wear sunglasses!

Effect, on the other hand, is a noun; it is the outcome.

The side effect of too much sun can be sunburn or even sun poisoning.

HESI HINT: If you can put an article (a, an, or the) in front, the correct version is most likely effect.

Can/May and Could/Might

Can is used to show ability; however, it is often used incorrectly to ask permission. Often, people will ask things like Can I go to the bathroom? or Can I help you? Although these are not grammatically incorrect, they are technically asking about ability, rather than permission.

May is used to gain permission and is seen as more polite than can. Asking May I go to the bathroom? or May I help you? illustrates that you are fully capable but are asking permission to continue.

Might is used when there is only a possibility, when something is uncertain. People tend to use might when they are discussing something that may or may not happen. For instance, if I am still deciding whether I want to attend a party, I would say I might attend, leaving my options open and not fully committing..

Could is sometimes used to show possibility, but is more often used to describe ability. People tend to say, you could do that or I could do that, speaking in terms of what is possible and what they are able to do.

Amount/Number

There is an easy trick to remember for when to use amount versus number. If it is possible to count a number of the things, use the word number. The word number is used to describe specific countable items. Let’s look at an example:

A large number of tickets were left unsold.

Since you could count the number of tickets, you would use the word number here.

On the other hand, amount is used for uncountable things. Things like liquids, abstract concepts, and some measures of time cannot be directly counted, so you would use amount.

Her amount of experience landed her the job.
The amount of snow made it difficult to play the football game.

Learn/Teach

Learn and teach describe the same overall idea, but opposite actions. To learn means to receive and take in information, whereas to teach means to give information to someone else.

We learn about shapes in math class.
The math professor teaches us about shapes.

Farther/Further

Farther is used when referencing physical distance. Notice the word far in the word farther; this is used any time you are discussing the literal measure of travel.

We’re almost there! Just a little bit farther!

Further is used any time you are discussing the need for more of something figuratively or abstractly. For instance, you would use further when talking about the need for further time or further research.

She wants to further her career by getting her doctorate.

Good/Well

Recognizing the difference between good and well can also be answered through your knowledge of the parts of speech.

Good is used to describe nouns and is an adjective. So, you could say “The burger was good!”

Well is used to describe a verb, so it is an adverb. When you are sick, this is why you should say, “I don’t feel well”. Feel is a verb, meaning well, and fits better than good as the descriptor.

Here/Hear

Here references places, like where you are standing or where you live.

I have a house here, right down the street!

Hear describes the ability to process sounds. A trick to remembering this commonly confusing pair is to look at the word ear in the word hear.

I can’t really hear you; can you speak up?

Lie/Lay

Lie versus lay is truly one of the most challenging verb pairs in English, and many fluent adults still confuse the two without even knowing it.

Lie means to rest or recline. This is the word you would use to explain you are going to sleep, resting on a hammock, or relaxing on a picnic blanket. The challenge here comes in the verb tenses. The past tense of the word lie is lay.

I lie down on the hammock.
I lay down on the hammock yesterday afternoon.

Lay means to put something down or place something on top. This is the word you would use if you are talking about an object that you are interacting with. The past tense of lay is laid.

I lay my phone on the table while I wash the dishes.
I laid my phone on the towel while I took a swim.

If there is no object you are interacting with, it is most likely lay. If you are doing it on your own, it is lie.

Among/Between

Between is used only when discussing two things. For instance, if you need to choose between chocolate and vanilla ice cream.

The campsite is between the two gas stations.

However, among is used when there are more than two options. Say there is an ice cream shop with fifteen flavors, you would need to choose among all the possibilities.

The mountains are scattered among many states.

Which/That

Which is used to describe non-essential parts of a sentence. It is used to add extra information to a sentence, and is usually paired with commas.

My new car, which is a pre-owned Volvo, has great gas mileage.

That is used to introduce necessary parts of the sentence; in other words, it is required in order to fully understand the sentence and the noun it is introducing.

The sweater that I gave her…
The restaurant that just opened…

Fewer/Less

Similar to amount and number, the use of fewer and less depends on whether the thing you are discussing is countable.

Fewer is used with countable items, people, or things.

There are fewer books in my classroom than in the library.

Less is used with uncountable nouns.

There is less daylight during the winter months.

Bad/Badly

Here is another commonly confused pair that can be helped by your knowledge of the parts of speech.

Bad is an adjective; it is used to describe a noun.

The movie I saw last night was bad.
The food was bad after being left out.

Badly is an adverb; it used to describe actions (verbs).

He writes badly.
The choir sings badly after not having enough practice.

i.e./e.g.

Although not full words, these two are still commonly confused.

The notation i.e. means in essence; it is used to clarify or summarize a point you are making.

He is a zoologist, i.e., someone who studies animals.

The notation e.g. means example given; it is used when you are providing a specific example for something you have explained or introduced.

I have many favorite books, e.g., The Bluest Eye by Toni Morrison.

Both of these are always followed by a comma.

Who/Whom and Whose/Who’s

Who is the subject of a sentence; it can be replaced with he, she, or they.

Who is at the door? He is at the door.

Whom is the object. It can almost always be replaced with him, her, or them.

To whom should I send this letter? To her.

HESI HINT: Use the replacement method! If he/she/they fits, use who. If him/her/they fits, use whom.

Whose refers to belonging; it is possessive.

Whose sweatshirt is this?
I don’t know whose dog that is.

Who’s is a contraction for who is, or sometimes who has.

Who’s going to the party next week?
Who’s taken a class by Professor Smith?

Bring/Take

Bring and take mean essentially opposite things.

To bring means to move closer to either you or the listener.

Can you bring me my water bottle?
I have an extra pair of cleats I can bring you!

To take means to move farther away from.

Do you mind taking that bag with you when you leave?
I took my library loans back to the library yesterday.

Accept/Except

Accept means simply to say yes or to take it in; it is a verb. You may get accepted into a college, or you could be hoping your job application is accepted by your dream company.

Except means anything but; except changes parts of speech based on how it is used in a sentence. Let’s look at this sentence: I love all fish except for salmon. In this sentence, except is being used as a preposition. However, there are rare instances in which except is used as a verb, meaning to exclude, as in “She was excepted from the club membership.”

Advice/Advise

Advice and advise mean similar things, but they are different parts of speech and are used in different ways.

Advice is a noun; it is a recommendation or guidance given verbally or in writing.

I have a hard time listening to my mom’s advice.

Advise is a verb; it means to give someone guidance or lead them in a certain way.

My mother advised me not to drive after midnight.

If you need to put the word in past, present, or future tense, it is advise.

“Could Have”, Not “Could of”

Although you may hear people say I could of done that or You could of come with us in your day-to-day conversations, this is grammatically incorrect. People sometimes write could of because of the way the contraction could’ve sounds when spoken aloud. However, could of is never correct.

Could have is the grammatically correct way to state the possibility of having done something.

If I hadn’t been sick, I could have gone.
I could have given you my sweatshirt if you were cold.