Question 99·Hard·Boundaries
Hundreds of meteor showers blaze through Earth’s atmosphere every year. Only eight of them, however, are considered major _____ the Quadrantids, Lyrids, Eta Aquariids, Perseids, Draconids, Orionids, Leonids, and Geminids—each capable of producing more than 20 meteors per hour at its peak.
Which choice completes the text so that it conforms to the conventions of Standard English?
For boundary questions, decide what the blank must connect: two complete sentences, or a main clause followed by extra information like a list. Use strict punctuation rules (e.g., semicolons join independent clauses). Then choose the option that introduces the list cleanly and fits the punctuation already used elsewhere in the sentence.
Hints
Identify the purpose of the blank
Look at what comes immediately after the blank: is it a new sentence, a list, or more description of the same idea?
Think about how semicolons work
Ask yourself whether the words after the blank form a complete sentence. If not, that can eliminate semicolon choices.
Focus on the word "namely"
How is "namely" typically punctuated when it introduces specific examples in the middle of a sentence?
Scan for punctuation patterns
Does the sentence already use a dash later on? If so, consider whether the blank needs to match that structure.
Step-by-step Explanation
Understand what the blank is doing
The sentence first mentions "major events" and then immediately names specific meteor showers: "the Quadrantids, Lyrids, Eta Aquariids, Perseids, Draconids, Orionids, Leonids, and Geminids." So the blank must introduce an explanatory list that renames or specifies those "major events."
Recognize the role of "namely"
The word "namely" signals that the writer is about to give the exact names of what was just mentioned. In standard English, it is commonly followed by a comma when it introduces examples ("namely, ...").
Apply rules for semicolons
A semicolon is used to join two independent clauses or to separate complex list items. Here, the text after the blank begins an explanatory construction (not a new independent clause), so placing a semicolon right after "events" is not appropriate. Also, putting a semicolon immediately after "namely" ("namely;") is not a conventional way to introduce examples.
Check colons and avoid incorrect doubling
A colon can introduce a list, but using a second colon right after "namely" ("namely:") creates an incorrect double-colon structure. That punctuation does not follow standard conventions for introducing examples.
Choose punctuation that correctly sets off the list
An em dash can introduce a parenthetical explanation, and the sentence already uses a dash later, so starting the list with an em dash works smoothly: "major events—namely, the Quadrantids, ... and Geminids—each capable of producing ..." Therefore, the correct answer is events—namely,.