箭在弦上

Explanation: Arrow has been upon the string. Compared to such circumstances, had to take some action. 　　Usage: The main predicate; as object; metaphor in critical condition 　　Source: Three Weichen Lin "as Yuan Shao Xi Yuzhou" Li Shan cited "Wei Zhi": "arrow in the string can not not fat." 　　Examples: I think the villain in text grudges is not worth it. As for me, in fact, but ~. ("Letters To Lu Xun Yang Ji-yun") 　　Riddle: Cited but not fat Thesaurus:  at daggers drawn, Hone Huohuo, hang by a hair, Ku salvo, Ku for days, may be triggered at any moment, weigh heavily ghost, Zhang pull crossbow arrow, Harden oneself To be, Li mill to be