Articles in Fixed Expressions
English articles usually follow strict grammatical rules, but idioms and fixed expressions have a mind of their own. For example, why do we say someone is in a hurry but did something by mistake? In these set phrases, you cannot rely on standard noun rules—memorizing the exact expression is the only way to master them.
This challenge tests your knowledge of these tricky exceptions through real-world scenarios, from helping a detective finish an incident report to completing a spy's encrypted message. You will practice identifying indefinite article phrases (like at a loss or make a fuss), definite article idioms (like out of the blue or take the liberty), and zero-article expressions (like catch sight of or in detail).
You'll work through 12 questions in a varied mix of single-choice, multi-choice, drop-down, and drag-and-drop formats.
Try the quiz to check your knowledge!
Correct Answers
I am currently at a loss to explain how the suspect managed to delete the classified files. He claimed he did it by no article mistake, but I was under the impression that the system required a complex password and two-factor authentication.
at a loss: This is a fixed idiom meaning "uncertain" or "unable to know what to do or say," and it always requires the indefinite article "a".
by mistake: In English, many phrases starting with "by" that describe how something happens (e.g., by chance, by accident, by mistake) do not take an article.
under the impression: This fixed expression means "believing something (often wrongly)" and always uses the definite article "the".
The correct answers are The new waiter was in a hurry and dropped the soup. and I am at a loss to explain why the oven exploded.
In English, certain fixed expressions require the indefinite article "a" or "an" and cannot be changed or omitted.
- "In a hurry" is the correct fixed expression (not "in hurry").
- "At a loss" is correct (meaning confused or not knowing what to do).
- "Make a fuss" requires the article (so "make fuss" is incorrect).
Help the HR manager complete her incident report.
During the meeting, Marcus ___ to the director's suggestion that the team should work on Saturdays.
The correct answer is took exception.
The phrase "take exception to" is a fixed expression meaning to strongly object to or be offended by something. It is always used with the zero article (no article), never "an exception" or "the exception."
The correct answers are I boarded the wrong flight to Antarctica by mistake. and To make matters worse, I had packed only beach clothes.
Sometimes the rule is that there is no article at all! These are called "zero article" fixed expressions.
- "By mistake" never takes an article (never "by a mistake" or "by the mistake").
- "To make matters worse" is a set phrase that does not use "the" before "matters." Adding an article breaks the idiom!
It's incredibly hard to make a living as a sculptor these days. Getting a solo gallery exhibition is completely out of the question without the right connections. I hope you don't take no article offense, but I might need to borrow some money to buy my next block of marble!
make a living: This fixed collocation means "to earn enough money to support oneself" and always requires the indefinite article "a".
out of the question: This idiom means something is "impossible" or "not allowed," and it always takes the definite article "the".
take offense: This phrase means "to feel insulted" and acts as an uncountable concept here, taking zero article.
Choose the correct phrase to complete the assistant's slightly presumptuous email.
Since you were unreachable during your silent yoga retreat, I ___ of upgrading your flight to first class using your miles.
The correct answer is took the liberty.
The fixed expression "take the liberty of (doing something)" means to do something without asking for permission first, usually assuming it will be appreciated. It always takes the definite article "the".
Choose the correct phrase for each gap to help Sarah finish her dramatic text message to her best friend about a terrible first date.
He made such a fuss about the restaurant's lighting, and then he spilled red wine on my favorite dress completely by mistake; honestly, I don't think we are going to be compatible in the long run.
He made such a fuss about the restaurant's lighting, and then he spilled red wine on my favorite dress completely by mistake; honestly, I don't think we are going to be compatible in the long run.
make a fuss: This expression, meaning "to complain or become angry about something minor," requires the indefinite article "a".
by mistake: Prepositional phrases indicating how something was done (like by accident, by chance, by mistake) typically use no article (zero article).
in the long run: This idiom, referring to a long period of time in the future, always takes the definite article "the".
Please keep an eye on the target's apartment from the van. If you catch no article sight of anyone leaving through the back door, notify me immediately. We cannot afford to be left in the dark about his movements tonight.
keep an eye on: This idiom means "to watch someone or something carefully" and uses the indefinite article "an" (because "eye" starts with a vowel sound).
catch sight of: This fixed phrase means "to suddenly notice or see someone/something" and requires zero article.
in the dark: When used metaphorically to mean "uninformed" or "ignorant about something," this idiom always takes the definite article "the".
Complete the head chef's performance review of his well-meaning but chaotic new assistant by choosing the correct expression for each gap.
I explained the complicated recipe to him in detail, specifically asking him to keep an eye on the simmering sauce, and although he is a decent cook on the whole, he still managed to burn the garlic!
I explained the complicated recipe to him in detail, specifically asking him to keep an eye on the simmering sauce, and although he is a decent cook on the whole, he still managed to burn the garlic!
in detail: When we explain something thoroughly, the phrase takes no article (zero article).
keep an eye on: This idiom, meaning "to watch carefully," requires the indefinite article "an".
on the whole: This fixed phrase, meaning "generally speaking," requires the definite article "the".
The correct answers are The promotion came completely out of the blue. and I was under the impression that he was quitting!
Many idioms rely on the definite article "the" to sound natural.
- "Out of the blue" means unexpectedly. Omitting the article ("out of blue") is incorrect.
- "Under the impression" means believing something to be true.
- "On the whole" means generally or mostly. Using "a" instead of "the" ("on a whole") is a very common mistake!
Help Detective Miller complete her case notes about a very clumsy suspect by choosing the correct phrase for each blank.
The suspect left the crime scene in a hurry, claiming that the heavy chandelier had fallen completely out of the blue. However, the evidence strongly suggests he broke it on purpose to create a distraction.
The suspect left the crime scene in a hurry, claiming that the heavy chandelier had fallen completely out of the blue. However, the evidence strongly suggests he broke it on purpose to create a distraction.
in a hurry: This fixed expression always requires the indefinite article "a".
out of the blue: This idiom, meaning "unexpectedly," always uses the definite article "the".
on purpose: This phrase, meaning "intentionally," takes no article (zero article).
Complete the veteran spy's advice to his new partner.
Remember, rookie: we always sweep the hotel room for hidden microphones as ___.
The correct answer is a matter of course.
The idiom "as a matter of course" means doing something as a standard habit, natural reflex, or regular procedure. It strictly requires the indefinite article "a".
Article
A/an vs the vs no article: the three-way choice that trips up learners whose first language has no articles (Russian, Japanese, Korean, Mandarin). Each option changes meaning — I saw a dog (any dog) vs I saw the dog (the specific one) vs Dogs are loyal (the species).
Articles are determinatives that mark noun specificity. A/an = indefinite, first mention. The = definite, known referent. Zero article = generic or uncountable.
Diagnostic: ask does the listener already know which one? Yes → the. No, and it's countable singular → a/an. Generic or uncountable → zero article.
Determiner
Determiner vs adjective: both appear before a noun, but determiners specify which/how many while adjectives describe what kind. Determiners come first: the big cat (✅) vs big the cat (❌). You can stack adjectives (big fluffy cat) but generally only one determiner per noun.
A determiner is a function slot before a noun filled by articles, demonstratives, possessives, or quantifiers.
Diagnostic: does the word tell you which one or how many rather than what kind? → determiner. Does it describe a quality? → adjective.
Phrase
Phrase vs clause: a phrase has NO subject-verb pair (on the table, the old man). A clause HAS a subject-verb pair (the man sat, because she left). This is the fundamental structural division in grammar — clauses contain phrases, not the other way around.
A phrase = group of words functioning as one unit: noun phrase, verb phrase, prepositional phrase, adjective/adverb phrase. No subject + verb.
Diagnostic: does the word group have both a subject AND a verb? Yes → clause. No → phrase. Name the head word to identify the phrase type (noun = NP, preposition = PP, etc.).
Preposition
Preposition vs particle: same words (in, on, up, off), different jobs. A preposition links to a noun (look at the book). A particle changes verb meaning without a noun (give up = quit). Test: is there a noun/pronoun after it forming a prepositional phrase? → preposition. Does it change the verb's meaning? → particle in a phrasal verb.
A preposition = small word connecting a noun to the sentence (time, place, manner, relationship). Choice is idiomatic per verb/adjective combination.
Diagnostic: struggling with which preposition to use? It's almost never about logic — look up the specific verb/adjective + preposition combination.
Verb
Verb vs noun vs adjective: nouns name things. Adjectives describe. Verbs express what happens or what IS. The test: can it take tense (walked, will walk)? Can it take -ing? Can it follow to as an infinitive (to walk)? Yes to any → verb. English often converts freely between classes (run = noun or verb), so context decides.
A verb = action/state/occurrence word. 5 forms (base, -s, past, past participle, -ing). Carries tense, aspect, mood, voice. The one required element in every sentence.
Diagnostic: does it change for tense (walk → walked)? Can you put to before it (to walk)? Does it take -ing (walking)? → verb.
Collocations
Collocation vs idiom: both are fixed expressions, but collocations are transparent (you can guess the meaning from the words: heavy rain = a lot of rain), while idioms are opaque (kick the bucket ≠ literally kick anything). Collocations are about which words pair naturally; idioms are about hidden meaning.
Collocations are habitual word combinations: make a decision, strong coffee, take a shower. Grammar allows alternatives, but fluency demands the conventional pairing.
Diagnostic: if the meaning is clear but the combination sounds "off" to native ears (do a mistake instead of make a mistake) — it's a collocation issue.
Idiom
Idiom vs collocation: both are fixed expressions, but idioms are opaque — the meaning is hidden (kick the bucket ≠ literally kicking). Collocations are transparent — the meaning is clear (heavy rain = a lot of rain). Collocations sound wrong if you swap words; idioms make no sense if you translate literally.
An idiom is a fixed phrase whose meaning can't be derived from its parts. They must be learned whole — and they're everywhere in casual and native English.
Diagnostic: does the literal meaning make sense? Yes → probably a collocation. No (absurd or unrelated) → idiom.
B2 | Upper Intermediate
B2 vs C1: B2 means effective communication on complex topics with some effort. C1 means effortless fluency with precise register control. If you can argue a point but still reach for words and make structural slips under pressure, you're B2.
B2 is the upper-intermediate CEFR level: mixed conditionals, complex passives, reported speech with backshift, participle clauses, and sustained written argument.
Diagnostic: does your writing read as "competent non-native" or "could be native"? The former → B2. The latter → C1.
Hard
Hard vs Medium: Medium tests one rule with realistic distractors. Hard tests interacting rules, edge cases, or context-dependent answers where multiple options seem correct until you think deeply. If you're scoring 80%+ on Medium, try Hard to find your real gaps.
The Hard tag filters for B2+ challenges with layered difficulty: rule interactions, subtle distractors, and contexts that demand genuine grammatical reasoning.
Diagnostic: if Hard questions feel impossible, drop to Medium and master the individual rules first. Hard assumes you already know each rule — it tests whether you can apply them together.