1.
People who stay up all night are usually exhausted the next day.
Correct Answer
A. Correct with no commas
Explanation
"Who stay up all night" is not parenthetical: if you remove it, the meaning of the sentence changes significantly.
2.
Greeks who speak Turkish are rarely Christians.
Correct Answer
A. Correct with no commas
Explanation
"Who speak Turkish" is not parenthetical: if you remove it, the meaning of the sentence changes significantly.
3.
The books which you can find in a library have usually been vetted by librarians.
Correct Answer
A. Correct with no commas
Explanation
"Which you can find in a library" is not parenthetical: if you remove it, the meaning of the sentence changes significantly.
4.
Canadians who live in Quebec all speak French.
Correct Answer
A. Correct with no commas
Explanation
"Who live in Quebec" is not parenthetical: if you remove it, the meaning of the sentence changes significantly.
5.
Meat which has passed its sell-by date often turns interesting colours.
Correct Answer
A. Correct with no commas
Explanation
"Which has passed its sell-by date" is not parenthetical: if you remove it, the meaning of the sentence changes significantly.
6.
Houses which have thatched roofs require re-thatching every few decades.
Correct Answer
A. Correct with no commas
Explanation
"Which have thatched roofs" is not parenthetical: if you remove it, the meaning of the sentence changes significantly.
7.
Students who study Classics have more fun than other students.
Correct Answer
A. Correct with no commas
Explanation
"Who study Classics" is not parenthetical: if you remove it, the meaning of the sentence changes significantly.
8.
The philosophers who lived before Socrates are known as pre-Socratics.
Correct Answer
A. Correct with no commas
Explanation
"Who lived before Socrates" is not parenthetical: if you remove it, the meaning of the sentence changes significantly.
9.
We have no works surviving from the poets who lived before Homer.
Correct Answer
A. Correct with no commas
Explanation
"Who lived before" and even "Who lived before Homer" are not parenthetical: if you remove either of those, the meaning of the sentence changes significantly.
10.
I would love to find all the Greek tragedies which have been lost.
Correct Answer
A. Correct with no commas
Explanation
"Which have been lost" is not parenthetical: if you remove it, the meaning of the sentence changes significantly.
11.
The ancient Greek tragedies which were written thousands of years ago are still performed today.
Correct Answer
D. Needs commas after "tragedies" and "ago"
Explanation
"Which were written thousands of years ago" is parenthetical: if you remove it, the meaning of the sentence does not change significantly, since by definition all ancient Greek tragedies were written thousands of years ago.
12.
I love to read the works of Homer who created magnificent epics.
Correct Answer
B. Needs a comma after "Homer"
Explanation
"Who created magnificent epics" is parenthetical: if you remove it, the meaning of the sentence does not change significantly, since there is only one Homer. If in fact you wanted to argue that there are two Homers, one who composed epics and one who did not, you would need to say "the Homer who created...".
13.
My mother who is a doctor has told me to get a flu shot this year.
Correct Answer
D. Needs commas after "mother" and "doctor"
Explanation
"Who is a doctor" is parenthetical: if you remove it, the meaning of the sentence does not change significantly. Using this clause without commas suggests that the speaker has more than one mother, so that the relevant one can be identified by her profession.
14.
I envy the Classics students who get to read ancient texts.
Correct Answer
B. Needs a comma after "students"
Explanation
"Who get to read ancient texts" is parenthetical: if you remove it, the meaning of the sentence does not change significantly. Using this clause without commas suggests that only some Classics students get to read ancient texts.
15.
I think we should throw away this meat which has passed its sell-by date.
Correct Answer
B. Needs a comma after "meat"
Explanation
"Which has passed its sell-by date" is parenthetical: if you remove it, the meaning of the sentence does not change significantly. Using this clause without commas suggests that only some of this meat is out of date.
16.
The Dutch who now all learn English in school write English better than we do.
Correct Answer
D. Needs commas after "Dutch" and "school"
Explanation
"Who now all learn English in school" is parenthetical: if you remove it, the meaning of the sentence does not change significantly. Using this clause without commas suggests that only some Dutch people now learn English in school, but that is at variance with the "all".
17.
Canadians who have a bilingual country are individually monolingual.
Correct Answer
D. Needs commas after "Canadians" and "country"
Explanation
"Who have a bilingual country" is parenthetical: if you remove it, the meaning of the sentence does not change significantly. Using this clause without commas suggests that only some Canadians have a bilingual country, but the country belongs to them all equally.
18.
People who share 40% of their DNA with yeast have more in common with other species than we used to realize.
Correct Answer
D. Needs commas after "people" and "yeast"
Explanation
"Who share 40% of their DNA with yeast" is parenthetical; if you remove it, the meaning of the sentence does not change significantly. Without the commas this sentence would imply that only some people share 40% of their DNA with yeast, but the sharing of DNA is a species-wide phenomenon.
19.
Home ownership which used to be a widely accessible goal is now becoming the preserve of the lucky few.
Correct Answer
D. Needs commas after "ownership" and "goal"
Explanation
"Which used to be a widely accessible goal" is parenthetical: if you remove it, the meaning of the sentence does not change significantly.
20.
The most dangerous prisoners who are typically serving long sentences are kept in separate prisons.
Correct Answer
D. Needs commas after "prisoners" and "sentences"
Explanation
"Who are typically serving long sentences" is parenthetical; if you remove it, the meaning of the sentence does not change significantly.