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Verbal·Standard English Conventions·Boundaries
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Many mechanical calculators were powered by a notched cylinder mechanism called the Leibniz wheel. Leibniz wheel calculators were popular in the first half of the twentieth __________ these ingenious devices were eventually replaced by electronic calculators.
Which choice completes the text so that it conforms to the conventions of Standard English?
A
century,
B
century
C
century, but
D
century that