百度百科：开弓没有回头箭，kāi gōng méi yǒu huítóujiàn，俗语，意思是拉开弓就要把箭射出去。
英语翻译：to be determined to reach one's goals in spite of setbacks; lit. once you've shot the arrow, there's no getting it back (idiom); to have to finish what one started; fig. once you started sth, there's no turning back
