English Grammar & Syntax Quiz: Proofreading Apostrophe Errors
10 questions · exam conditions
0:00
Proofreading Apostrophe ErrorsQuestion 1 of 10

Aisha and Ben jointly wrote one report, but each prepared a separate revenue forecast.

Which sentence most accurately conveys the intended ownership?

Aisha's and Ben's joint report includes Aisha and Ben's separate revenue forecasts.
Aisha and Ben's joint report includes Aisha and Ben's separate revenue forecasts.
Aisha and Ben's joint report includes Aisha's and Ben's separate revenue forecasts.
Aisha's and Ben's joint report includes Aisha's and Ben's separate revenue forecasts.
← Back to quizzes

English Grammar & Syntax Quiz

English Grammar & Syntax Quiz: Proofreading Apostrophe Errors

Practice Proofreading Apostrophe Errors in English Grammar & Syntax with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Proofreading Apostrophe Errors, giving you a quick way to practice the rules, question types, and explanations that matter most for English Grammar & Syntax.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

Aisha and Ben jointly wrote one report, but each prepared a separate revenue forecast.

Which sentence most accurately conveys the intended ownership?

  1. Aisha's and Ben's joint report includes Aisha and Ben's separate revenue forecasts.
  2. Aisha and Ben's joint report includes Aisha and Ben's separate revenue forecasts.
  3. Aisha and Ben's joint report includes Aisha's and Ben's separate revenue forecasts. (correct answer)
  4. Aisha's and Ben's joint report includes Aisha's and Ben's separate revenue forecasts.
Explanation: When you see possessives with multiple nouns, the key question is: do they share ownership, or does each own something separately? English signals this through apostrophe placement — joint ownership uses one apostrophe on the last noun only, while separate ownership requires an apostrophe on each noun. In the passage, Aisha and Ben together wrote one report (joint ownership), but each individually prepared a forecast (separate ownership). The sentence that correctly mirrors this is C: "Aisha and Ben's joint report includes Aisha's and Ben's separate revenue forecasts." Here, "Aisha and Ben's" (single apostrophe on Ben) correctly signals the shared report, while "Aisha's and Ben's" (apostrophe on each name) correctly signals that each person owns a distinct forecast. A gets it backwards — "Aisha's and Ben's joint report" uses separate-ownership punctuation for something they own together, which is contradictory. It also incorrectly writes "Aisha and Ben's separate revenue forecasts," implying they share those forecasts jointly. B correctly writes "Aisha and Ben's joint report" for shared ownership, but then uses "Aisha and Ben's separate revenue forecasts" — the same joint-ownership form — for the forecasts, contradicting the word separate. You can't signal joint ownership and separate ownership with the same apostrophe structure. D makes the same mistake as A on the report ("Aisha's and Ben's"), though it correctly handles the forecasts. Two errors don't cancel out. Quick tip: Let the meaning guide the punctuation. If you can substitute "they share one X," use one apostrophe at the end. If you mean "each has their own X," add an apostrophe to every name.

Question 2

The sentence must identify a consultant whose recommendations were adopted and must also state that the consultant has been retained for another project.

Which sentence uses whose and who's correctly?

  1. The consultant who's recommendations we adopted is the analyst who's been retained for the next project.
  2. The consultant whose recommendations we adopted is the analyst whose been retained for the next project.
  3. The consultant whose recommendations we adopted is the analyst who's been retained for the next project. (correct answer)
  4. The consultant who's recommendations we adopted is the analyst whose been retained for the next project.
Explanation: When you see whose and who's in a question, ask yourself one thing first: does the word show possession, or is it a contraction? Whose is the possessive form (like "his" or "her"), while who's is simply a contraction of who is or who has. You can always test this by expanding the contraction — if "who is" or "who has" fits naturally in the sentence, use who's. If not, use whose. Answer C is correct because each word is used in exactly the right role. In the first clause, "the consultant whose recommendations we adopted," the word shows ownership — the recommendations belong to the consultant — so the possessive whose is correct. In the second clause, "the analyst who's been retained," you can substitute "who has been retained," which reads perfectly, confirming the contraction who's is appropriate there. Answer A flips both words incorrectly. "Who's recommendations" expands to "who is recommendations," which is nonsense — recommendations aren't a predicate. Answer B gets the first clause right (whose recommendations ✓) but then uses "whose been retained," which would mean the analyst possesses "been retained" — that makes no grammatical sense. Answer D reverses the errors from C, using who's where possession is needed and whose where the contraction belongs. A reliable strategy: whenever you encounter whose/who's, immediately try substituting "who is" or "who has." If the sentence still makes sense, use the contraction who's. If it breaks down, you need the possessive whose. This quick swap catches errors every time.

Question 3

Installation required three weeks of work. A separate scheduling problem then caused a delay of one day.

Which sentence correctly expresses both measures using possessive time expressions?

  1. After three week's work, the project experienced a days' delay.
  2. After three weeks' work, the project experienced a day's delay. (correct answer)
  3. After three weeks work, the project experienced a days delay.
  4. After three week's work, the project experienced a day's delay.
Explanation: When a unit of time functions as a possessor — describing the duration that "owns" something (like work or a delay) — you treat it as a possessive noun, complete with an apostrophe. The rule mirrors standard possessives: singular nouns take 's, while plural nouns ending in s take just an apostrophe after the s. Here, "three weeks" is plural, so the possessive form is weeks' (apostrophe after the s). "One day" is singular, so the possessive form is day's (apostrophe before the s). Answer B — three weeks' work and a day's delay — applies both rules correctly, making it the right choice. Answer A gets the plural wrong by writing week's, which would mean a single week owns the work, contradicting "three." It also writes days', which is plural-possessive, but the passage describes only one day's delay — singular is required. Answer D makes the same mistake with week's for the plural, even though it correctly handles day's. Both A and D share the trap of adding 's to a plural noun, which creates a singular possessive instead of a plural one. Answer C omits apostrophes entirely from both expressions, treating them as simple noun modifiers rather than possessives — grammatically incorrect in formal writing. A useful memory trick: before placing the apostrophe, decide whether the time noun is singular or plural first. If it's plural and ends in s, the apostrophe goes after (weeks'). If it's singular, add 's (day's). Getting that order right will protect you on any possessive time-expression question.

Question 4

Several chief financial officers submitted reports. The reports compare the performance of several companies during the decade beginning in 1990.

Which sentence correctly uses apostrophes for the plural abbreviation, the plural possessive noun, and the decade?

  1. The CFO's reports compare the company's performance during the 1990's.
  2. The CFOs reports compare the companies' performance during the 1990s.
  3. The CFOs' reports compare the companies' performance during the 1990s. (correct answer)
  4. The CFOs' reports compare the companies performance during the 1990's.
Explanation: When a question tests apostrophe use across multiple contexts at once, break it into three separate decisions: plural abbreviations, plural possessives, and decades. Plural abbreviations like CFOs follow standard pluralization rules — just add s, no apostrophe. The apostrophe only appears when showing possession. Since the reports belong to the CFOs (multiple chief financial officers), you need the plural possessive: CFOs' (plural first, then apostrophe after). Plural possessives for nouns like companies work the same way: form the plural first (companies), then add only an apostrophe (companies') because the word already ends in s. The reports compare performance belonging to multiple companies, so companies' is correct. Decades like the 1990s are simply pluralized with an s — no apostrophe needed, since nothing is being omitted or owned. That makes C — CFOs' reports compare the companies' performance during the 1990s — the correct answer. Choice A uses CFO's, which implies one CFO, and 1990's, which incorrectly treats the decade as possessive. Choice B correctly pluralizes the decade (1990s) and possessives companies', but writes CFOs reports without any apostrophe — leaving out the possessive entirely, as if the reports don't belong to the CFOs. Choice D correctly uses CFOs' but drops the apostrophe from companies (making it non-possessive) and incorrectly adds one to 1990's. A useful rule of thumb: apostrophes signal either possession or contraction — never simple plurals. If you're just making something plural, keep the apostrophe out.

Question 5

The organization's style guide forms the possessive of every singular personal name by adding 's, including names already ending in s. One invoice belongs to Mr. Harris, and the accountant represents the entire Harris family.

Which sentence follows the stated style guide and correctly distinguishes the individual from the family?

  1. Mr. Harris' invoice was forwarded to the Harrises' accountant.
  2. Mr. Harris's invoice was forwarded to the Harris's accountant.
  3. Mr. Harrises' invoice was forwarded to the Harrises's accountant.
  4. Mr. Harris's invoice was forwarded to the Harrises' accountant. (correct answer)
Explanation: Possessive formation gets tricky when names end in s, and it gets even trickier when you need to distinguish one person from an entire family. Here, the style guide gives you a clear rule for singular names: always add 's, even if the name ends in s. The family name, however, follows standard plural possessive rules — you pluralize the name first (Harrises), then add only an apostrophe (Harrises'). That logic makes D the correct answer. Mr. Harris's follows the style guide's singular rule (one person, add 's), and Harrises' correctly shows possession by the entire Harris family (pluralized to Harrises, then the apostrophe follows the final s). Choice A uses Harris' for the singular possessive, which directly violates the style guide's explicit instruction to add 's to all singular names — even those ending in s. It gets the family possessive right, but one error disqualifies it. Choice B correctly applies Harris's for the singular, but then writes Harris's again for the family — treating the family as if it were a single person rather than a plural group. The word Harris's can only represent one individual named Harris. Choice C is doubly wrong: Mr. Harrises' treats a single person's name as if it were already plural, which makes no grammatical sense, and Harrises's incorrectly adds 's after an already-plural noun. As a study tip, always tackle these questions in two steps: identify whether the noun is singular or plural first, then apply the correct possessive rule. Mixing up those two steps is exactly the trap the wrong answers are designed to set.

Question 6

A memorandum refers to recommendations submitted by two advisory committees and a final decision made by one regional director.

Which sentence correctly uses apostrophes to reflect the relationships described?

  1. The two advisory committees' recommendations were reviewed before the regional director's decision. (correct answer)
  2. The two advisory committee's recommendations were reviewed before the regional director's decision.
  3. The two advisory committees' recommendations were reviewed before the regional directors' decision.
  4. The two advisory committee's recommendations were reviewed before the regional directors' decision.
Explanation: When forming possessives, you need to think about two things simultaneously: how many of each noun exist, and where the apostrophe goes relative to that number. This question tests both at once. The passage gives you clear signals: two advisory committees and one regional director. Start there. For a plural noun that ends in -s (like "committees"), you form the possessive by adding only an apostrophe after the final s: committees'. For a singular noun (like "director"), you add apostrophe + s: director's. Answer A does exactly this — "committees'" reflects multiple committees sharing ownership of the recommendations, and "director's" reflects a single director owning the decision. A is correct. Answer B fails on the first noun: "committee's" is the possessive of a single committee, but the passage specifies two. Placing the apostrophe before the s signals singular possession, which contradicts the passage. Answer C gets the committees right but mishandles the director. "Directors'" is the possessive of multiple directors, but the passage names only one regional director. This is the mirror-image error of B. Answer D combines both mistakes — "committee's" (singular instead of plural) and "directors'" (plural instead of singular). Every apostrophe is in the wrong place. A useful strategy: before writing any possessive, ask yourself "How many?" first, then decide apostrophe placement. Singular → apostrophe + s. Plural ending in s → s + apostrophe. Locking in the quantity first prevents the kind of rushed errors that make B, C, and D tempting distractors.

Question 7

A company publishes one handbook for its entire workforce. The handbook lists emergency contacts supplied by several employees.

Which sentence correctly uses an attributive noun for the handbook and a possessive noun for the contacts?

  1. The employee handbook lists the employees' emergency contacts. (correct answer)
  2. The employee's handbook lists the employees' emergency contacts.
  3. The employees' handbook lists the employee's emergency contacts.
  4. The employees handbook lists the employees emergency contacts.
Explanation: When a noun modifies another noun to describe its type or purpose — without showing ownership — it functions as an attributive noun and takes no apostrophe. When a noun genuinely owns something, it needs a possessive apostrophe. This question tests whether you can apply both rules correctly in a single sentence. The passage gives you two key facts: the handbook belongs to one company and serves the entire workforce (so it's a shared resource, not individually owned), and the emergency contacts were supplied by several employees (plural ownership). The sentence needs an attributive noun for the handbook — meaning "handbook" is simply described by its type (employee handbook, like "employee training" or "employee lounge") — and a plural possessive for the contacts. That's exactly what answer A delivers: employee is an attributive noun with no apostrophe, and employees' correctly shows plural possession over the contacts. Answer B uses employee's handbook, implying one specific employee owns the handbook — contradicting the passage, which says it's a company-wide resource. Answer C reverses the logic entirely: employees' handbook suggests the workforce collectively owns it (wrong context), while employee's emergency contacts limits the contacts to a single person when multiple employees supplied them. Answer D drops apostrophes everywhere — employees handbook and employees emergency contacts — leaving both relationships grammatically undefined and incorrect. A useful habit: before adding an apostrophe, ask yourself, "Is this noun describing a type, or is it showing ownership?" If it's just a label (like employee handbook or safety manual), no apostrophe is needed.

Question 8

Two employees are married to sisters. The compliance file contains a signed approval from each employee's mother-in-law.

Which sentence correctly identifies the two approvals?

  1. The compliance file contains both mother's-in-law signed approvals.
  2. The compliance file contains both mothers-in-law's signed approvals. (correct answer)
  3. The compliance file contains both mothers'-in-law signed approvals.
  4. The compliance file contains both mother-in-laws' signed approvals.
Explanation: When you need to pluralize and show possession for a compound noun like mother-in-law, you must handle two operations carefully: where to add the plural, and where to add the apostrophe. For compound nouns, the main noun carries the plural. In mother-in-law, the main noun is mother — the -in-law part is a modifier. So the correct plural is mothers-in-law, not mother-in-laws. Once you have the plural, forming the possessive is straightforward: add 's to the end of the complete plural word, giving you mothers-in-law's. Choice B — mothers-in-law's — correctly pluralizes at the main noun (mothers) and places the possessive apostrophe after the full plural form. This is your answer. Choice A (mother's-in-law) treats the singular mother as the possessive unit and inserts the apostrophe mid-compound, which fractures the structure incorrectly. Choice C (mothers'-in-law) gets the plural right but places the apostrophe immediately after mothers, as if the compound ended there — it doesn't. Choice D (mother-in-laws') makes the classic error of pluralizing at the end of the whole compound rather than at the main noun; mother-in-laws is not a recognized plural form in standard English. A reliable tip: whenever you see a hyphenated compound noun, mentally identify which word is the head noun (the noun doing the core work), pluralize that word, and then tack the possessive 's onto the very end of the full compound. This two-step check will protect you from all three of the traps this question sets.

Question 9

A clinic maintains one waiting area for several children and another waiting area for several parents.

Which revision correctly combines the references to the two areas?

  1. The clinic will redesign the childrens' and parent's waiting areas.
  2. The clinic will redesign the children's and parent's waiting areas.
  3. The clinic will redesign the childrens' and parents' waiting areas.
  4. The clinic will redesign the children's and parents' waiting areas. (correct answer)
Explanation: When combining two plural possessives in a single sentence, you need to think carefully about two things: how to form the plural of an irregular noun, and where to place the apostrophe for each possessive. Start with children. This is an irregular plural — the word doesn't add an -s to become plural; it changes its spelling entirely (child → children). Because the plural form already ends in -en rather than -s, you form the possessive by adding 's, giving you children's. Now consider parents. This is a regular plural — it adds -s to become plural (parent → parents). For regular plurals ending in -s, you form the possessive by adding only an apostrophe after the s, giving you parents'. Combined, the correctly revised sentence reads: The clinic will redesign the children's and parents' waiting areas. That's answer D. Answer A writes childrens', treating children as if it were a regular plural ending in -s and placing the apostrophe after that imaginary s — but childrens is not a word at all. It also uses parent's (singular possessive), contradicting the passage's reference to several parents. Answer B gets children's right but uses parent's (singular), which ignores the fact that the passage specifies multiple parents requiring the plural possessive parents'. Answer C repeats the childrens' error from A, and although parents' is correctly formed, the answer is still wrong because childrens' is not a valid word. Your study tip: whenever you see a possessive question, first ask "Is this noun a regular or irregular plural?" Irregular plurals (like children, women, men) take 's; regular plurals ending in -s take only an apostrophe.

Question 10

Which sentence correctly distinguishes the contraction it's from the possessive forms of it?

  1. Although it's revised its schedule, the agency says the final decision is its alone. (correct answer)
  2. Although its revised it's schedule, the agency says the final decision is its alone.
  3. Although it's revised its schedule, the agency says the final decision is it's alone.
  4. Although its revised its schedule, the agency says the final decision is it's alone.
Explanation: Whenever you see it's versus its on a grammar exam, remember one rule: it's is always a contraction meaning "it is" or "it has," while its is always a possessive pronoun (like "his" or "her") — and possessive pronouns never use apostrophes. To check any sentence, mentally substitute "it is" or "it has" wherever you see it's. If the substitution makes sense, the apostrophe belongs. If it sounds wrong, you need the possessive its. Option A is correct because every usage passes this test. "It's revised its schedule" expands to "it has revised its schedule" ✓, and "its schedule" correctly shows possession without an apostrophe ✓. The final "its alone" is also a possessive, correctly written without an apostrophe ✓. Option B fails immediately: "its revised" tries to use a possessive where a contraction ("it has revised") is needed, and then "it's schedule" wrongly applies an apostrophe to a possessive noun — a double swap that breaks both rules. Option C gets the first clause right but stumbles at the end: "it's alone" expands to "it is alone," which changes the meaning entirely. The sentence intends to say the decision belongs to the agency (its alone), not that the decision is alone. Option D makes the opposite error from A in the first clause — using the possessive its where "it has revised" requires a contraction — and then repeats C's mistake with the final it's. Your go-to strategy: always try the "it is / it has" swap. If the expanded version sounds natural, use the apostrophe; if it sounds awkward, drop it.