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Idiom questions on the ACT are different from the other grammar questions on the ACT. Why? Idiom questions don’t conform to specific rules. You have to rely on your intuitive grasp of English and your familiarity with certain phrases.

Because you’re likely to encounter at least a few idiom questions on the ACT English test, I’ll provide you with some information about idioms that should help you raise your ACT English score.

In this post, I’ll do the following:

• Explain the concept of an idiom.
• Detail the most common types of idiom questions on the ACT English section.
• Offer strategies to help you identify and correctly answer idiom questions.
• Give a thorough list of idioms to help guide your studying.
• Provide you with ACT English practice questions to test you on what you’ve learned.

What Is an Idiom?

Idioms are phrases or expressions that do not conform to simple rules. Each idiom, by definition, is unique. Most people think of idioms as expressions that often have figurative meanings different from their literal meanings. Examples of this type of idiom include "actions speak louder than words," "barking up the wrong tree," and "make a long story short." However, the ACT does not test you on these colloquial expressions. ACT English idiom questions will test you on different types of idioms.

Idioms have no rules.

How Are Idioms Tested on the ACT English Section?

While the ACT doesn't test you on the figurative expressions I referenced above, the ACT does test you on two types of idioms: prepositional idioms and idioms with gerunds/infinitives.

Prepositional Idioms

For prepositional idioms, you must know which prepositions to use with a given word based on the context of the sentence. For example, you should say that you "wonder about" something, not "wonder on" something. You're "suspicious of" something, not "suspicious by" something. There is no rule to determine the correct preposition to use. You must be familiar with the phrase or rely on what you think "sounds right." Here's an example sentence with a prepositional idiom:

Unsurprisingly, after Corey decided not to pay back the substantial loan given to him by his best friend, everyone was outraged for Corey’s behavior.

This is a typical sentence with an idiom error you may encounter on the ACT. There's no violation of a specific grammar rule in the sentence. However, the phrase "outraged for" is incorrect. The sentence should read:

Unsurprisingly, after Corey decided not to pay back the substantial loan given to him by his best friend, everyone was outraged by Corey’s behavior.

The proper expression is "outraged by." There is no rule that allows you to determine the correct idiomatic expression. Familiarity with the given phrases will greatly help you in identifying idiom errors.

There's another type of idiom that is commonly tested on the ACT.

Idioms with Gerunds or Infinitives

Gerunds are verbs that are used as nouns and end in "ing." Examples of gerunds include skipping, talking, and performing. Infinitives are verbs used as nouns and are constructed by using the word "to" plus a verb. Examples of infinitives include to do, to analyze, and to explain.

So what are some examples of idioms with gerunds or infinitives? The correct phrase is "capable of being," not "capable to be." The proper idiomatic expression is "regarded as being," not "regarded to being." For these types of idioms, you need to know which preposition to use and whether to use a gerund or an infinitive.

With some idioms, depending on the context, it's acceptable to use an infinitive or a gerund. Here's an example with the gerund in bold:

I neglected doing my homework.

The sentence is also correct if you use an infinitive:

I neglected to do my homework.

While both of those sentences are correct, this is a sentence with an idiom error:

Shelby will succeed in to graduate from college.

The phrase "succeed in to graduate" is incorrect. Do you know the right idiomatic expression to use? This is the corrected version of the sentence:

Shelby will succeed in graduating from college.

There's no rule to learn that will indicate that "succeed in graduating" is the correct phrase. Here's one more example of an idiom error:

Gina decides leaving the group when we go out.

This is how the sentence looks after we fix the idiom error:

Gina decides to leave the group when we go out.

The infinitive form should be used with the word "decides." Now here are couple of actual idiom questions from real ACTs.

Real ACT English Examples

Try to answer this idiom question from a real ACT:

Explanation: The answer is D. The right idiomatic expression is "sat across from."

Here's one more for you: 

The court agreed with Kevin that a person's right for wearing clothing of his or her own choosing is, in fact, protected by the Fourteenth Amendment. 

A. NO CHANGE

B. of wearing

C. to wear

D. wearing

Explanation: The correct expression is “right to wear clothing of his or her own choosing." The answer is C.

Why Are Idiom Questions Difficult/Easy?

Why They're Difficult

Idiom questions can be challenging because other grammar questions follow specific rules or patterns that can be applied to all sentences. Idiom questions test your knowledge of specific idiomatic expressions. Literally, there are thousands of idioms. It's not practical to try to remember each one.

Furthermore, ESL students are less likely to be able to identify idiom errors. Knowledge of idioms tends to be built throughout a lifetime of exposure to them.

Why They're Easy

Idiom questions are the only ones where solely relying on what "sounds right" is likely to give you the right answer. These questions do not require you to understand and apply a rule. If you're familiar with the specific idioms that appear on the ACT English section, you can easily spot any idiom errors. 

ACT English Tips for Idiom Questions

#1: If a preposition, gerund, or infinitive is underlined, check for idiom errors.

#2: The question may be testing idioms if the answer choices are all prepositions.

#3: Keep a list of idioms that appear on your practice tests.

#4: Review and familiarize yourself with the list of idioms below.

List of ACT Idioms

While there are thousands of idioms in the English language, almost all idiom questions I’ve encountered on the ACT involve prepositional idioms or idioms with gerunds/infinitives. I've listed some of the more common prepositional idioms and idioms with gerunds/infinitives to help guide your studying. Idioms that have appeared on questions in the Real ACT Prep Guide (the red book) are listed first.

 It's not practical for you to memorize every single idiom on this list. There are usually less than a handful of idiom questions on the ACT English section. Spending numerous hours learning hundreds of idioms would not be the best use of your study time. 

However, I do recommend that you review this list periodically to become more familiar with these phrases. Thinking about proper idiom construction should benefit you when you encounter idiom questions on the ACT. You'll improve your intuitive grasp of idioms and be able to better recognize idiom errors.

After trying to learn every idiom

This is my extensive list of idioms:

IDIOMS FROM REAL ACT PREP GUIDE 

come to a conclusion

come to a halt

come to an end

earned a living from/by doing

in the dusk

modeled on

principles of

such as

PREPOSITIONAL IDIOMS

About

anxious about

ask about

bring about

curious about

hear about

think about

talk about

worry about

Against

advise against

argue against

count against

decide against

defend against

go against

rebel against

As

celebrate as

regard as

see as

view as

At

aim at

arrive at

laugh at

look at

succeed at

By

accompanied by

amazed by

confused by

followed by

go by

impressed by

organized by

struck by

For

advocate for

ask for

blame for

famous for

known for

last for

meant for

named for

necessary for

pay for

ready for

responsible for

tolerance for

strive for

wait for

watch for 

From

abstain from

different from

excuse from

far from

obvious from

protect from

Into

enter into

look into

inquire into

read into

In

engage in

fall in love

in A as in B

interested in

succeed in 

take in

Study hard!

On 

base on

draw on

focus on

impose on

insist on

move on

prey on

rely on

Over

argue over

rule over

talk over

think over

Of

approve of

capable of

certain of

characteristic of

combination of A and B

cure of

deprive of

die of 

a fan of

in danger of

in the hope of

in recognition of

made up of

a model of

an offer of

on the border of

remind of

a selection of

a source of

suspicious of

take advantage of

an understanding of

a wealth of

To

able to

accustomed to

adapt to

adhere to

admit to

adjacent to

agree to

as opposed to

belong to

central to

come to

contribute to

devoted to

in addition to

in contrast to

listen to

object to

prefer A to B

partial to

reluctant to

reply to

see to

similar to

a threat to

try to (NOT try and)

unique to

With 

agree with

bargain with

correlate with

familiar with

identify with

in keeping with

interfere with

sympathize with

trust with

You can do it!

GERUNDS VS. INFINITIVES

Verbs Followed by a Gerund

accuse of

admire for

allow

appreciate

capable of

complete

concentrate on

confess to

consider

delay

describe

discourage from

discuss

dislike

effective at

enjoy

escape

finish

forbid

imagine

insist on

permit

plan on

postpone

refrain from

report

resent

resume

stop

tolerate 

Prepositions Followed by a Gerund

before

after

without

Verbs Followed by an Infinitive

agree

attempt

choose

condescend

dare

decide

deserve

encourage

expect

fail

intend

love

mean

neglect

offer

plan

prepare

promise

refuse

scramble

seem

strive

swear

tend

threaten

want

Additional ACT English Practice Questions

Hooray for making it to this point in the article! I know that was a long list. By now, you should understand the concept of idioms and how idioms are tested on the ACT. I've created some realistic ACT English questions on idioms for you. Consider the proper construction of idiomatic expressions and try to answer these questions without referring to the list above.

1. My parents allow me staying out late because I have earned their trust. 

A. NO CHANGE

B. stayed

C. to stay

D. is staying

2. Despite his efforts, Gerald is incapable at eating without staining his shirt.

A. NO CHANGE

B. to eat

C. eating

D. of eating

3. Even though I tend to not enjoy magic, I was amazed to the trick the illusionist did at the end of his show.

A. NO CHANGE

B. by

C. from

D. into

4. Wyeth insisted on watching The O'Reilly Factor every single night.

A. NO CHANGE

B. insisted by

C. insisted in

D. insisted to

Answers: 1. C, 2. D, 3. B, 4. A

What's Next?

Congratulations on your continued efforts to improve your ACT English score. Make sure you check out this article on the five critical concepts you must understand to ace ACT English. Also, many students fear ACT English questions about commas; you don't have to live in fear.

If you're looking for a basic overview of the ACT English section, read about what's actually tested on ACT English.