once in a while & every once in a while：偶然

on occasion間或,有時 | once in a while & every once in a while偶然 | be at one's service隨時提供服務(wù),隨時效勞

once in a while & every once in a while：偶爾 隨時

on occasion間或,有時 | once in a while & every once in a while偶爾 隨時 | be at one's service隨時提供服務(wù),隨時效勞 同時

once for all：一勞永逸地

all at once 突然;同時;一起 . | once for all 一勞永逸地 . | once in a while 偶爾,間或 .

once for all：只此一次

once again再一次 | once for all只此一次 | once in a while有時,偶爾

Once a fortnight：每兩星期一次

每星期一次 Once a week | 每兩星期一次 Once a fortnight | 每月一次 Once a month

They go for a picnic in the park once in a while：他們偶爾到公園去野餐

once in a while偶爾,有時,間或: | They go for a picnic in the park once in a while. 他們偶爾到公園去野餐. | once more再一次,又一次:

once in a way：偶爾

once in a blue moon 千載難逢地 | once in a way 偶爾 | once in a while 偶爾

once in a way：破例

once in a blue moon 千載難逢 | once in a way 破例 | once in a while 偶爾

once in a way：偶

once for all 只此一次 | once in a blue moon 千載難逢地 | once in a way 偶

once in a while：偶爾,有時

once in a while 偶爾,間或 | once in a while 偶爾,有時 | once more 再一次,又一次