而且我知道，日期已经不能再改，是板上钉钉的事了。While I really want to attend the party， I'll be on a business trip. And I understand the date of the ceremony can't be changed. It's cast in stone.
来源：【贵州广播电视台-动静新闻】今日成语：衔石填海释义：比喻为实现既定目标，坚韧不拔地奋斗到底。成语出处：《山海经·北山经》：“ 炎帝 之少女名曰 女娃 。女娃 游于东海，溺而不返，故为精卫，常衔西山之木石，以堙於东海。
