Which sentence uses commas correctly with its appositive?
AMy sister a doctor just published her first book.
BMy sister, a doctor, just published her first book.
CThe novelist, Toni Morrison, wrote Beloved.
DA doctor, my sister just published her first book.
Option B is correct. 'A doctor' is a nonessential appositive — the sentence already clearly identifies the subject ('my sister'), so the appositive adds bonus information and is set off by commas. Option C is wrong: 'Toni Morrison' is essential (there are many novelists), so it gets no commas. Options A and D have structural problems with punctuation or placement.
Question 2 Multiple Choice
A student writes: 'The planet, Mars, is the fourth from the sun.' Is the comma use correct?
AYes — 'Mars' is extra information since there is only one planet under discussion
BNo — 'Mars' is essential to identify which planet; the correct form is 'The planet Mars is the fourth from the sun' with no commas
CYes — all appositive phrases always require commas
DNo — the entire sentence should be rewritten as two separate sentences
'The planet' is too vague to identify anything specific — there are eight planets. The name 'Mars' is essential to tell us which planet, so it receives no commas: 'The planet Mars is the fourth from the sun.' Adding commas implies the sentence is already specific ('my planet, Earth, …' could work if context made the referent clear), but 'the planet' without further context requires the essential appositive to complete its meaning.
Question 3 True / False
Removing a nonessential appositive from a sentence leaves the sentence still clearly identifying its subject — and this is exactly the test for whether commas are needed.
TTrue
FFalse
Answer: True
The essential/nonessential test works by mentally deleting the appositive and checking whether the remaining sentence still points clearly to the right person or thing. If yes — commas go in (it's nonessential). If no, because the sentence becomes too vague — no commas (it's essential). This test is reliable and applies to every appositive.
Question 4 True / False
Most appositives should be set off by commas.
TTrue
FFalse
Answer: False
Essential appositives — those necessary to identify the noun — receive no commas. 'The poet Langston Hughes wrote about the American dream' needs the name to specify which poet; adding commas would misrepresent the name as optional, bonus information. Commas signal 'you could remove this and the sentence still works,' which is false for essential appositives.
Question 5 Short Answer
How do you decide whether an appositive needs commas? Describe the test and explain why it works.
Think about your answer, then reveal below.
Model answer: Mentally remove the appositive from the sentence and ask: does the sentence still clearly identify its subject? If yes, the appositive is nonessential — add commas. If the sentence becomes too vague (you can no longer tell which person or thing is meant), the appositive is essential — use no commas. The test works because commas signal removable, bonus information. An essential appositive is not removable without losing the sentence's specific meaning.
The comma rule for appositives reflects a deeper grammatical principle: commas around embedded phrases signal that the phrase is parenthetical (optional). If the phrase is actually necessary for the sentence to make a specific claim, treating it as parenthetical misrepresents its role and can confuse the reader.