Rubicon
noun uk/ˈruː.bɪ.kɒn/ /ˈruː.bɪ.kən/ us/ˈruː.bɪ.kɑːn/
cross the Rubicon 破釜沉舟;下重大决心;采取断然行动
to do something that you cannot later change and will strongly influence future events
Most EU states have crossed the Rubicon and adopted the euro. 大多数的欧盟国家已经下了决心采用欧元。