Basics. Defining vs. Non-defining Relative Clauses: correct answers
Jump to answers ↓Defining vs. Non-defining Relative Clauses
Relative clauses add detail to your sentences, but punctuation changes everything. A defining relative clause provides essential information to identify the noun without commas (e.g., "The wand that sparks purple magic is dangerous"). A non-defining relative clause adds extra, non-essential information and must be separated by commas (e.g., "My brand-new laptop, which I bought yesterday, is broken"). Additionally, the pronoun that can never be used in a non-defining clause!
In this challenge, you will navigate eccentric scenarios like a wealthy widow's will, an alien tour guide's Earth manual, and an HR manager's workplace disaster report. You will practice identifying when information is essential or extra, applying correct comma punctuation, and choosing the appropriate relative pronouns (who, which, that, whose, and where).
You'll work through 12 questions presented in a variety of drag-and-drop, drop-down, single-choice, and multi-choice formats.
Try the quiz to check your knowledge!
Correct answers
Question 1
The correct answers are The soup I ordered was completely cold. and The waiter, who dropped my pizza, didn't even apologize.
The soup I ordered... is correct. In a defining relative clause, you can omit the relative pronoun (that/which) if it is the object of the clause (I ordered the soup).
The waiter, who dropped my pizza... is correct. It uses a non-defining relative clause properly separated by commas.
The chef, I spoke to earlier... is incorrect. You cannot omit the relative pronoun in a non-defining relative clause. It must be "The chef, whom/who I spoke to earlier, was very rude."
The dessert that it arrived last... is incorrect. The relative pronoun "that" replaces the subject "it", so you cannot use both ("that it"). It should be "The dessert that arrived last..."
Question 2
Complete the food critic's dramatic restaurant review by choosing the correct option for each blank.
The mushroom soup we ordered tasted like salty dishwater.
Chef Pierre , whose temper is legendary, threw a flying baguette across the room.
The head waiter , who was terrified, immediately hid behind the dessert cart.
The correct sentences are: The mushroom soup we ordered tasted like salty dishwater. Chef Pierre**, whose temper is legendary,** threw a flying baguette across the room. The head waiter**, who was terrified,** immediately hid behind the dessert cart.
we ordered is a defining relative clause. Because the relative pronoun (that/which) is the object of the verb "ordered," it can be completely omitted! No commas are needed.
Chef Pierre is a proper noun, so we use commas for extra information. Whose correctly shows possession (his temper).
The head waiter is a specific, unique role in the restaurant, so we use commas. Once again, that is never used in non-defining clauses!
Question 3
The correct answers are My nephew, who lives in London, will inherit the mansion. and The diamond necklace that is hidden in the safe goes to my cat.
My nephew, who lives in London, will inherit the mansion. is correct. It uses a non-defining relative clause (enclosed in commas) to give extra information about the nephew.
The diamond necklace that is hidden in the safe goes to my cat. is correct. It uses a defining relative clause (no commas) with the pronoun "that" to specify exactly which necklace is meant.
My favorite painting, that hangs in the hall... is incorrect because you cannot use "that" in a non-defining relative clause. It must be "which."
My husband, whom I met in Paris will receive... is incorrect because it is missing the closing comma after "Paris." Non-defining clauses in the middle of a sentence must be enclosed by two commas.
Question 4
Complete this angry traveler's online review by choosing the correct relative clause for each blank.
The creepy hotel where we stayed was supposedly haunted.
Sir Reginald , who haunts the third floor, kept stealing my socks every night.
The only suitcase that survived the trip is now full of green slime!
The correct sentences are: The creepy hotel where we stayed was supposedly haunted. Sir Reginald**, who haunts the third floor,** kept stealing my socks every night. The only suitcase that survived the trip is now full of green slime!
where we stayed defines exactly which hotel is being talked about, so no commas are needed. We use where for places (or in which).
Sir Reginald is a specific name, so the clause just adds extra information. This requires commas. We cannot use that after a comma!
The only suitcase requires a defining relative clause to specify it. We use that for things, and no commas are used.
Question 5
Mayor Higgins, who was last seen eating a giant donut, is our prime suspect. We need to find the specific donut shop that sells these rare rainbow sprinkles. The Golden Crumb Bakery, which is located on Main Street, was robbed at midnight.
When to use commas:
- When a person or place is uniquely identified by their proper name (Mayor Higgins, The Golden Crumb Bakery), any descriptive clause that follows is just extra information. This is a non-defining clause. It needs commas, and you must use "who" for people or "which" for things (never "that").
- When the noun is general and needs identification ("the specific donut shop"), the clause is defining. It provides essential information, so we use no commas and can use "that".
Question 6
A chaotic wizard has dropped his collection of wands on the floor! Help him identify the dangerous one by choosing the grammatically correct sentence.
The correct answer is The wand that sparks purple magic is completely out of control!
This is a defining relative clause because it tells us exactly which wand is dangerous out of all the wands on the floor. Defining relative clauses do not use commas.
- "The wand, that..." is incorrect because we never use "that" in a non-defining clause (with commas).
- "The wand which... magic, is..." is incorrect because it uses a single comma, which wrongly separates the subject from its verb.
- "who" is only used for people, not magical objects!
Question 7
The headmaster's pet owl, which delivers the mail, is quite grumpy today. Students should avoid any owls that look overly caffeinated. The Moonstone Elixir, which takes three weeks to brew, is highly explosive!
Defining vs. Non-defining Relative Clauses:
- Non-defining clauses give extra, non-essential information about a specific, unique noun (like "The headmaster's pet owl" or "The Moonstone Elixir"). They MUST be separated by commas, and you CANNOT use "that".
- Defining clauses give essential information that tells us which thing we are talking about (like "any owls"). They do NOT use commas, and "that" is the most common relative pronoun to use for things and animals.
Question 8
Complete the tech blogger's slightly dramatic review by selecting the correct clause.
My brand-new laptop, ________, is already making alarming clicking noises.
The correct answer is which I bought just yesterday.
The commas indicate that this is a non-defining relative clause (it adds extra information about the laptop). In non-defining relative clauses, we must use "which" for things.
You cannot use "that" after a comma in a relative clause, and you cannot omit the relative pronoun entirely if there are commas!
Question 9
The correct answers are Earthlings, who need oxygen to survive, are surprisingly fragile. and The planet, which is mostly covered in water, looks blue from space.
Both correct options properly use non-defining relative clauses with commas to add extra, non-essential information.
The humans, that drink coffee... is incorrect. You can never use the relative pronoun "that" immediately after a comma in a non-defining relative clause.
The sun that provides them with light... is incorrect. Because Earth only has one sun, "the sun" is a unique noun. Unique nouns require non-defining relative clauses (with commas and "which"). Writing it without commas implies Earth has multiple suns and we are specifying which one!
Question 10
Help the family historian caption the old photograph correctly by choosing the right phrase.
Uncle Arthur ________ claims to be an intergalactic time traveler.
The correct answer is , who always wears a tin foil hat,.
Because "Uncle Arthur" is a specific, named person, the relative clause gives us extra, non-essential information about him. This makes it a non-defining relative clause, which must be separated by commas.
We use "who" for people, and we cannot use "that" in non-defining relative clauses!
Question 11
Help the HR manager complete this incident report by choosing the correct clause for each blank. Pay close attention to commas!
The employee who caused the explosion is currently hiding under a desk.
Mr. Henderson , who loves his espresso, was unfortunately standing right next to the machine.
Our brand-new espresso machine , which cost a fortune, is now completely ruined.
The correct sentences are: The employee who caused the explosion is currently hiding under a desk. Mr. Henderson**, who loves his espresso,** was unfortunately standing right next to the machine. Our brand-new espresso machine**, which cost a fortune,** is now completely ruined.
who caused the explosion is a defining relative clause identifying which employee, so it doesn't use commas.
Mr. Henderson is a proper noun (a specific person), so we use a non-defining relative clause with commas. Remember, we cannot use that in non-defining clauses!
Our brand-new espresso machine is a specific, unique item, so it also takes a non-defining relative clause with commas and which.
Question 12
My father, who refuses to ask for directions, drove us straight into a swamp. Luckily, the brother who brought his GPS was in the car with us. Our rental van, which was already making weird noises, finally broke down completely.
Why the punctuation matters:
- You only have one father, so "My father" is already a uniquely identified person. The clause gives extra, humorous information, so it gets commas (non-defining).
- The phrase "the brother" implies there is more than one brother, so the clause "who brought his GPS" is essential to identify which brother we mean. No commas are used (defining).
- "Our rental van" refers to a specific, single vehicle they are using. The weird noises are extra info, so it requires commas and "which".