大动干戈　

◎ 大动干戈 dàdòng-gāngē

(1) [stage a war]∶干戈:古代两种兵器。指进行战争

(2) [make a big fuss over]∶比喻大张声势地行事

这事很简单,何必大动干戈呢

(3) [take effort to do]∶比喻大费手脚

(4) [attack brutally;strike violently]∶也指大打出手