O 開頭單詞

once-forbidden adj.一次禁戒的

once-firing 一次燒成

once upon a time 從前

once upon a potty

once too often 又一次；次數(shù)太多

once through tubular boiler [交通運(yùn)輸工程]直流式鍋爐

once through 單程的

once over

once more 再一次

once in a while

once in a way 偶爾

once in a lifetime love

once in a lifetime 一生一次

once in a blue moon 千載難逢；極為罕見

once for all 徹底地；一勞永逸地；只此一次

once every month 每月一次

once every four years 每四年一次

once caldas

once and for all change [經(jīng)濟(jì)學(xué)]一次性變動(dòng)

once and for all