Question

if necessary, add or remove commas from the sentence.
sirius blacks vocal coach a part - time opera singer
is usually very dramatic.

Explanation:

The phrase "a part-time opera singer" is a non-restrictive appositive that adds extra, non-essential information about Sirius Black's vocal coach. Non-restrictive appositives need to be set off from the main clause with commas on both sides.

Answer:

Sirius Black's vocal coach, a part-time opera singer, is usually very dramatic.