melt away           
phrasal verb with melt verb uk/melt/ us/melt/
 逐渐消失;逐渐散去
to disappear slowly
  As the police sirens were heard, the crowd started to melt away. 警笛一响,人群就开始散开了。 
  (强烈的情绪)变弱,消失
If a strong feeling melts away, you feel it less strongly and it disappears.
  Her anger melted away when she read the letter. 读到信时,她的怒火慢慢消失了。