你怎能说走就走
[nĭ zĕn néng shuō zŏu jiù zŏu]
'How can you leave just by saying?' This conveys a sense of questioning against partings or goodbyes. It shows an emotional plea or complaint to the abrupt disappearance or change by someone. Maybe because of this abrupt leaving caused some regretful or unforgettable stories that cannot easily get over in one's heart.