珍惜cherish/treasure;

　　把握seize;

　　回忆recall/recollect/reminisce;

　　怀旧nostalgia;

　　纪念in memory of/commemorate;

　　虚度waste/loiter/squander/idle away;

　　流逝time flies;

　　延迟delay/procrastinate;

　　转瞬即逝in a blink of an eye;

　　千载难逢once in a blue moon