This uses deletion - a technique where you remove specific letters from a word or phrase, often indicated by words like 'without', 'losing', or 'forgotten'.
Look for a word meaning 'live' at the start, then take 'pasts' and remove the letter that represents 'quietly' in musical terms (which gets 'forgotten').
Answer: BEASTS | BE (meaning 'live') + ASTS (from 'pasts' with 'p' for 'piano/quietly' removed/forgotten) = BEASTS