SAT OwlThe relationship that astronomer Henrietta Swan Leavitt discovered in 1912 between the brightness of certain pulsating stars and the time each star takes to complete one ______ gave astronomers a way to measure the distances to faraway galaxies.
Which choice completes the text so that it conforms to the conventions of Standard English?
pulse,
pulse
pulse;
pulse:
Show answer and explanation
Answer: B
Everything from "The relationship" through "one pulse" is the subject, and "gave" is the verb. The "that" clause is essential to identifying the relationship, so it takes no commas, and no punctuation can separate the subject from its verb.
Choice A is tempting because the subject is so long that a pause feels natural, but a comma cannot separate a subject from its verb.
Why the other choices are wrong
- A. A comma cannot separate the subject from its verb. The long subject ending in pulse connects directly to the verb gave without any punctuation.
- C. A semicolon is used to separate independent clauses or items in a list. It cannot split a subject from its verb within a single sentence.
- D. A colon introduces a list, explanation, or quotation. It is incorrect to place one between a subject and its verb in this context.
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