Comma Rules — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. An introductory word is a single word like "Meanwhile" or "Fortunately" that starts a sentence.
Single introductory words like "Meanwhile" or "Fortunately" set the tone or transition before the main clause, and a comma follows them.
2. In "After the assembly, the students returned to class," the comma comes after an introductory phrase.
"After the assembly" is a prepositional phrase that introduces the sentence, so the comma tells the reader where that introduction ends and the main idea begins.
3. The phrase "a famous inventor" in "Thomas Edison, a famous inventor, created the light bulb" is an appositive.
"A famous inventor" renames Thomas Edison and gives extra detail, making it an appositive that must be set off by commas.
4. If you remove an appositive from a sentence, the sentence should still make complete sense.
Because an appositive adds extra rather than essential information, removing it should leave behind a sentence that still makes complete sense on its own.
5. Introductory phrases often tell when, where, or how something happens.
Introductory phrases frequently answer "when," "where," or "how," providing context before the main action of the sentence.
6. In "Suddenly, the fire alarm went off," the word "Suddenly" is an introductory word.
"Suddenly" is a single introductory word (an adverb) that sets up the sentence, so a comma follows it before the main clause.
7. An appositive at the end of a sentence only needs one comma before it.
When an appositive comes at the very end of a sentence, there is no text after it, so only one comma is needed -- the one that introduces it.
8. The comma after an introductory element gives the reader a natural pause before the main idea.
The comma creates a natural pause that helps the reader mentally shift from the introductory setup to the main point of the sentence.
9. In "My cousin Jake, an excellent swimmer, won the race," the appositive tells us more about Jake.
The appositive "an excellent swimmer" adds more detail about Jake, helping the reader understand why he won the race.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
"Before the concert, we ate dinner at home."
→ Comma after an introductory phrase
Comma after an introductory word
"Next, stir the mixture until it is smooth."
→ Comma after an introductory word
Comma after an introductory clause
"The Amazon, the largest rainforest, is in South America."
→ Commas around an appositive phrase
Commas around an appositive phrase
"While we were sleeping, the first snow of winter fell."
→ Comma after an introductory clause
Comma after an introductory phrase
Correct matches: "Before the concert, we ate dinner at home." → Comma after an introductory phrase; "Next, stir the mixture until it is smooth." → Comma after an introductory word; "The Amazon, the largest rainforest, is in South America." → Commas around an appositive phrase; "While we were sleeping, the first snow of winter fell." → Comma after an introductory clause.