Final answer:
The sentence should be revised using the passive voice to shift the focus from the singer to the solo.
Step-by-step explanation:
The best reason to revise the sentence using the passive voice is that it shifts the focus from the subject (the person who sang the solo) to the object (the solo that was sung). In this case, the focus would be on the solo rather than the singer. By using the passive voice, the sentence becomes: 'A solo was sung by someone during the holiday concert.' This way, it does not matter if the name of the singer is unknown, as the focus is on the solo itself.
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