the holy grail

剑桥词典

(also the Holy Grail)
a cup believed to have been used by Jesus Christ at the meal before his death
圣杯（传说耶稣在最后的晚餐上使用过）

something that is extremely difficult to find or get
极难找到（或得到）之物
Sustained nuclear fusion is the holy grail of the power industry . 能持久反应的核聚变是电力工业梦寐以求的“圣杯”。 返回 the holy grail