Relative Clauses with Quantifiers
Combining a quantifier with a relative pronoun allows you to specify a portion of a group in a single, elegant sentence. For example, instead of writing a comma splice like "I bought five apples, two of them are bad," you should use a relative clause: "I bought five apples, two of which are bad." This structure always uses an object pronoun after the preposition: whom for people, which for things, and whose for possession.
This challenge tests your ability to apply these advanced rules across a variety of bizarre scenarios. You will decide between which for objects (like cursed antique clocks and rock-hard fruitcakes), whom for people (like dragon-taming job candidates and wandering tourists), and the tricky possessive whose (for eccentric aunts with insulting parrots). You'll also practice identifying correct structures with quantifiers like neither, none, half, and some to avoid sneaky comma splices.
You'll work through 10 questions in a fun mix of single-choice, multi-choice, drop-down, and drag-and-drop formats.
Try the quiz to check your knowledge!
Correct Answers
The correct answers are: We hired five new software engineers, three of whom insist on sleeping under their desks. We hired five new software engineers; three of them insist on sleeping under their desks. We hired five new software engineers, and three of them insist on sleeping under their desks.
When connecting two independent clauses, you cannot simply use a comma and a pronoun like "them" (this creates a comma splice). You must use a relative pronoun after a preposition (three of whom), use a semicolon (; three of them), or add a conjunction (, and three of them). Also, remember to use the object pronoun whom rather than who after the preposition "of".
Help the food critic finalize their rather scathing review of the amateur baking contest by dragging the correct phrases into the gaps.
The annual village bake-off featured twelve spectacular fruitcakes, none of which could be cut with a standard kitchen knife. The head judge glared at the four amateur bakers, all of whom were desperately trying to hide their suspiciously store-bought packaging.
The annual village bake-off featured twelve spectacular fruitcakes, none of which could be cut with a standard kitchen knife.
Because there are twelve fruitcakes (more than two), we use the quantifier "none" instead of "neither." We must use the relative pronoun "which" rather than "them" to connect the clauses; using "none of them" would create a grammatically incorrect comma splice.
The head judge glared at the four amateur bakers, all of whom were desperately trying to hide their suspiciously store-bought packaging.
Following a preposition like "of," we must use the object pronoun "whom" when referring to people. "All of who" is grammatically incorrect, and "all of those" would create a comma splice.
The museum recently acquired twelve "haunted" paintings, none of which have been properly cataloged yet.
To join the two clauses without using a conjunction (like "and"), we must use a relative pronoun. "None of them" would create a grammatical error called a comma splice. Since "paintings" are things, we use "which."
I also found three antique dolls in the basement, two of whose glass eyes seem to follow me around the room.
We need a possessive relative pronoun here because the "glass eyes" belong to the dolls. "Whose" is the only relative pronoun that indicates possession, and it can be used for both people and things.
Finish the art critic's review of a very peculiar modern art exhibition by selecting the grammatically correct option.
The gallery featured works by several local artists, _____ sculptures were made entirely of recycled cheddar cheese.
The correct answer is two of whose.
We need a possessive relative pronoun to indicate that the sculptures belong to the artists. "Whose" is the correct possessive relative pronoun.
When combined with a quantifier, the structure is [quantifier] + of + whose + [noun].
"Several of which" would incorrectly imply the artists are objects, and "whom's" is not a real word.
We spent the morning wrangling thirty tourists, half of whom wandered off to take selfies with a very angry moose.
When a relative pronoun follows a preposition (like "of"), we must use the object form "whom" for people, not "who." Using "half of them" would result in a comma splice because "them" is a personal pronoun, not a relative pronoun.
By noon, we had lost five expensive cameras in the lake, all of which belonged to me, thankfully!
"All of which" is correct because "cameras" are things (requiring "which"). "Neither of which" is incorrect because "neither" only refers to exactly two items, but here there are five cameras. "All of them" would cause a comma splice.
Complete the scientific journal's summary of Dr. Finklebaum's latest academic disaster.
At the conference, Dr. Finklebaum proposed two entirely absurd theories, _____ made the slightest bit of sense to his peers.
The correct answer is neither of which.
First, because the sentence specifies exactly two theories, we must use the dual quantifier "neither" rather than "none" (which is used for three or more).
Second, to avoid a comma splice, we need a relative pronoun to link the clauses. Since "theories" are things, we use "which". "Neither of them" would create a run-on sentence, and "that" cannot be used directly after a preposition in a non-defining relative clause.
The correct answers are: two of whose parrots kept insulting my cooking. all of whom brought uninvited and unruly pets. and none of their husbands offered to wash the dishes.
To show possession in a relative clause with a quantifier, we use "of whose" + noun (e.g., two of whose parrots).
When referring to people as the object of the preposition "of", we must use whom, not "who".
"Two of their parrots" creates a comma splice, but adding the conjunction "and" makes "and none of their husbands" grammatically correct.
Help the HR manager complete her slightly concerning hiring report by choosing the correct phrase.
The committee interviewed fifteen candidates for the dragon-tamer position, _____ had any actual experience with fire-breathing reptiles.
The correct answer is none of whom.
Because the two clauses are joined only by a comma, we must use a relative pronoun to create a non-defining relative clause. "None of them" would create a comma splice (two independent clauses improperly joined by a comma).
Furthermore, because the pronoun follows the preposition "of" and refers to people (candidates), we must use the objective case "whom" rather than "who" or "which."
The correct answers are none of which have ever told the correct time. and half of which are currently ticking backwards.
In a non-restrictive relative clause referring to things, we use a quantifier + "of" + "which" (e.g., none of which, half of which).
"Some of them" creates an illegal comma splice. "All of that" is incorrect because we cannot use "that" after a preposition in a relative clause. "Two of which they" is incorrect because it contains a double subject ("which" and "they").
Complete the intergalactic zoologist's field notes about a newly discovered planet by dragging the correct phrases into the blanks.
During the expedition, we encountered five distinct alien species, some of whose defense mechanisms included emitting a scent like burnt toast. We also collected hundreds of peculiar glowing rocks, several of which began to hum softly in the cargo bay.
During the expedition, we encountered five distinct alien species, some of whose defense mechanisms included emitting a scent like burnt toast.
We need a possessive relative pronoun here because the "defense mechanisms" belong to the alien species. "Some of whose" perfectly bridges the gap. "Some of which" would be grammatically broken here, and "some of them" creates a comma splice.
We also collected hundreds of peculiar glowing rocks, several of which began to hum softly in the cargo bay.
When referring to inanimate objects (rocks) in a non-defining relative clause, we use "which." "Whom" is reserved exclusively for people (or highly personified beings), and "many of them" would result in a comma splice because there is no coordinating conjunction.
Clause
Clause vs phrase: a clause has a subject + verb (she runs); a phrase does not (in the morning, running fast). This is the first distinction to make when analysing sentence structure.
A clause is a grammatical unit built around a verb: independent clauses make complete sentences; dependent clauses attach to them as modifiers or complements.
Diagnostic: find the verb. If there's a subject doing or being something → clause. If there's no subject-verb pair → phrase.
Comma
Comma vs semicolon vs period: all three can appear between two complete thoughts. Comma + conjunction (I left, and she stayed). Semicolon alone (I left; she stayed). Period = full stop (I left. She stayed.). Using just a comma between two independent clauses without a conjunction is a comma splice — the most common comma error.
The comma ( , ) separates sentence parts: lists, non-essential info, introductory phrases, and clauses before coordinating conjunctions.
Diagnostic: are both sides complete sentences with no conjunction between them? Don't use a comma alone — upgrade to a semicolon or add a conjunction.
Complex sentence
Complex vs compound sentence: a compound sentence links two equal independent clauses with and/but/or. A complex sentence links an independent clause with a subordinate (dependent) clause — one idea is the main point, the other is background.
A complex sentence = independent clause + dependent clause. The dependent clause adds time (when), reason (because), condition (if), or detail (who/which).
Diagnostic: are both halves able to stand alone? Yes → compound. Can only one stand alone? → complex.
Coordination
Coordination vs subordination: coordination joins equals (I sang and she danced — both independent). Subordination makes one element depend on another (I sang because she danced — one clause is background). Coordination builds compound sentences; subordination builds complex sentences.
Coordination links elements of equal weight using and, or, but. All coordinated items must be grammatically parallel — noun + noun, phrase + phrase, clause + clause.
Diagnostic: are both sides of the conjunction doing the same grammatical job? Yes → coordination. Is one side background/explanation for the other? → subordination.
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.
Negation
Single vs double negatives: standard English uses ONE negative per clause (I don't see anything or I see nothing). Double negatives (I don't see nothing) are grammatical in many languages and some English dialects, but are non-standard in written/formal English. This is the #1 negation trap for speakers of Spanish, Russian, and French.
Negation = not after auxiliary/modal, or do-support. Negative words (never, nobody, nothing) negate alone without adding not.
Diagnostic: count the negatives in the clause. More than one? → double negative. Fix by replacing one with a positive (anything, anyone, ever).
Possessive
Noun possessive vs pronoun possessive: nouns ADD an apostrophe for possession (Sarah's, students'). Pronouns NEVER use apostrophes (its, yours, theirs — no apostrophe). This contradiction is why its/it's is the most common error in English writing.
The possessive marks ownership: 's for singular nouns, s' for plural nouns ending in s, and special pronoun forms (my/mine, their/theirs).
Diagnostic: is it a noun? → add 's or s'. Is it a pronoun? → use the built-in possessive form (NO apostrophe). Specifically its (possessive) vs it's (it is).
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.
Pronoun
Pronoun vs noun: nouns name explicitly (Sarah, the book). Pronouns substitute and point back (she, it). Pronouns are a closed class (you can't invent new ones easily), while nouns are open (new ones appear constantly). The main complication: pronouns still carry case marking that nouns have lost.
A pronoun replaces a noun or noun phrase. Types: personal, demonstrative, relative, interrogative, reflexive, indefinite.
Diagnostic: every pronoun must have a clear antecedent (the noun it replaces). If the reader can't tell which noun a pronoun refers to → ambiguity error.
Punctuation
Punctuation vs grammar: grammar governs word forms and order. Punctuation governs how you mark the structure on paper. You can have perfect grammar with wrong punctuation (comma splices in otherwise correct sentences), and you can have correct punctuation with broken grammar. They're parallel systems.
Punctuation = the system of marks that make written sentence structure visible: periods, commas, semicolons, colons, apostrophes, dashes, and quotation marks.
Diagnostic: if your grammar is correct but readers misparse your sentences → punctuation problem. If punctuation is fine but word forms/order are wrong → grammar problem.
Relative clause
Restrictive vs non-restrictive: this distinction changes meaning. The students who passed celebrated = only those who passed. The students*, who passed,** celebrated* = all students passed and all celebrated. One missing comma flips the meaning of the entire sentence.
A relative clause = dependent clause modifying a noun. Restrictive (essential, no commas) vs non-restrictive (extra, commas required).
Diagnostic: remove the clause. Does the sentence still identify the right noun? Yes → non-restrictive (add commas). No (now ambiguous) → restrictive (no commas).
C1 | Advanced
C1 vs C2: C1 means fluent and flexible use with occasional gaps in very unfamiliar domains. C2 means native-like command of idiom, irony, and register across any subject. If you can handle advanced grammar but still miss cultural nuance or very rare idioms, you're C1.
C1 is the advanced CEFR level: inversion, cleft sentences, subjunctive mood, advanced conditionals, and precise register control in professional and academic contexts.
Diagnostic: can you write persuasively in different registers and catch subtle irony? Consistently → C2. Sometimes → 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.