The Great Wall of China _______ was built over many centuries _______ remains one of humanity's greatest architectural achievements.
2
readingWhich choice completes the text so that it conforms to the conventions of Standard English?
A
which was built over many centuries
B
, which was built over many centuries,
C
—which was built over many centuries
D
, which was built over many centuries—
Correct Answer: B
Choice B is the best answer. This question tests comma usage with nonrestrictive clauses.
- Context clues: There's only one Great Wall of China, so the clause is nonessential.
- Meaning: Nonrestrictive clauses are set off by commas on both sides.
- Verify: "The Great Wall of China, which was built over many centuries, remains..." correctly adds extra information.
💡 Strategy: When the subject is unique (proper noun), use ", which" with commas for additional info.
Choice A is incorrect because it lacks commas. Choice C is incorrect because a single dash creates asymmetry. Choice D is incorrect because it mixes comma and dash incorrectly.