5

Set 16: Boundaries

Explanation

Answer: C

PASSAGE

The fossil, which was recently authenticated, _______ recently.

Which choice completes the text so that it conforms to the conventions of Standard English?

A. discovering
B. been discovered
C. was discovered✓ Correct
D. were discovered

Detailed Answer Explanation

The correct answer is 'was discovered' because of the rule: passive voice agreement. Passive voice constructions require the correct form of "to be" plus the past participle. The form of "to be" must agree with the subject in number. A singular subject like "artifact" requires "was" not "were."

Key Evidence:

• "The fossil, which was recently authenticated, _______ recent..."

Why others are wrong: A ('discovering' is active voice and creates an incomplete sentence), B ('been discovered' lacks the auxiliary verb "has" or "had" needed to complete the verb phrase), D ('were discovered' uses plural "were" with a singular subject).