放得下的是曾经放不下的是回忆
[fàng dé xià de shì céng jīng fàng bù xià de shì huí yì]
The user might be trying to communicate the contrast between the past (曾经, cengjing), where things are gone but remain unforgettable (记忆 jiyi). This signifies acceptance over past incidents but holding on strongly onto the memories associated with them.