He once won the first prize

曾经───once

On hearing that the new novel was published, he rushed at once to the bookshop for a copy.───听说那本小说出版了, 他就迫不及待地跑到书店去买.

I met Miquela once, briefly.───我见过蜜凯拉一次，时间很短。

Once you're stuck in deep snow, it's difficult to lever yourself out.───你一旦陷进深雪中, 那就很难出来.

She braced herself up and tried once more.───她鼓起勇气又试了一次.

Let's go through the sonata once more.───这个奏鸣曲咱们再练习一遍.

Once a knave, ever a knave.───一次成无赖, 永远是无赖.

She guessed the right answer at once.───她立刻猜出了正确的答案.

He determined to go [ that he ( should ) go ] at once.───他决心立刻就 走.

Once you've given your word, don't try to back out.───一旦许下诺言, 就不要想翻悔.

Slavery was once socially sanctioned.───奴隶制曾经为社会所认可.

The word once spoken can never be realled.

Once again , the train was late.

He that once deceives is ever suspected.

Once on shore, we pray no more.

Once bit [bitten] twice shy.

Hear twice before you speak once.

Measure thrice before you cut once.

He didn't approach the front door at once.

If necessary I can come at once.