Question 24·200 Super-Hard SAT Reading Questions·Standard English Conventions
Early twentieth-century astronomers reexamined the much-discussed Martian “canals.” With sharper telescopes, they found that the “canals” were uneven bands of light and shadow, ______ were not the straight, engineered waterways that earlier observers had drawn.
Which choice completes the text so that it conforms to the conventions of Standard English?
Locate the main clause before the blank and check whether the words after the blank form another complete sentence (subject + verb). If both are independent clauses, you need a strong boundary (most often a period or a semicolon). Then confirm that any transition word (like however) is punctuated in a standard way and that the next sentence starts with a capital letter.
Hints
Test for complete sentences
See whether the words before the blank could stand alone as a complete sentence, and whether the words after the blank could also stand alone.
Watch out for a comma splice
If both sides are complete sentences, a comma (even with however) is usually not enough.
Check capitalization after a period
If you choose an option with a period, the next sentence should start with a capital letter.
Step-by-step Explanation
Identify the clauses on each side of the blank
Before the blank: “With sharper telescopes, they found that the ‘canals’ were uneven bands of light and shadow” is an independent clause.
After the blank: “They were not the straight, engineered waterways...” is also an independent clause.
Choose punctuation that correctly separates independent clauses
A comma alone cannot separate two independent clauses (that would create a comma splice). You need a stronger boundary (like a period) between them.
Check that the transition word is placed correctly
However can appear at the end of the first sentence, followed by a period and a new sentence starting with a capital letter.
Select the choice that creates a correct sentence
The choice that correctly ends the first independent clause and begins the next one is however. They.