希望渺茫

forlorn hope
    希望渺茫
    forlorn hope means plan or undertaking that is almost certain not to succeed，幾乎不可能實現(xiàn)的計劃或不可能成功的事情。
    舉例：
    Going to there rescue in a rowing-boat is a bit of a forlorn hope.
    乘劃艇去救他們，希望不大。
    It has another mean that is 'an advance guard of troops sent on a hazardous mission'， 敢死隊派往完成危險任務(wù)的一支先遣部隊。