Select the option that expresses the given sentence in direct voice.
The professor explained that although the theory had been considered correct for centuries, new findings now proved that it was flawed.
Show answer & explanation
Correct answer: C
Explanation
To convert the given sentence from indirect speech ('The professor explained that although the theory had been considered correct for centuries, new findings now proved that it was flawed') to direct speech, we need to reverse the changes in tense and time/place references that occur during the conversion to indirect speech.
The reporting verb 'explained' is in the past tense, so the tenses in the direct speech inverted comma must be changed to their original present forms.
'had been considered' (past perfect) reverts to 'was considered' (past simple) or 'has been considered' (present perfect). The continuous state over centuries makes 'was considered' or 'has been considered' acceptable, but 'was considered' is a common usage for past general truths or long-held beliefs that are now being challenged.
'now proved' (past simple) reverts to 'now prove' (present simple).
'it was flawed' (past simple) reverts to 'it is flawed' (present simple).
Option C correctly makes these tense adjustments.