天塌地陷　

◎ 天塌地陷 tiāntā-dìxiàn

(1) [natural disasters like giant earthquakes and landslides]∶天坍塌,地裂陷。比喻重大灾变

(2) [serious]∶形容事情严重

天塌地陷的事,他也等明天再说