but once

You have had your present already. Christmas comes but once a year.

你已经得到了圣诞礼物。圣诞节可是一年只有一次哦。

Once, he did dive for cover but he soon reappeared and continued his activities.

他确实一度销声匿迹，但是很快就重出江湖，继续他的各种活动。

The batsman began slowly but once he got his eye in he started to play some very good shots.

那个击球手起步较慢,但是当他的眼光变得准确起来后,他打了几个很好的球.

He tried to speak, but for once, his voice had left him.

他想说话，却一时语塞。

Christmas comes but once a year, you can diet in the New Year.

圣诞节一年才一次，你过了年再减肥吧。

Now, she attributes much of her understanding of college to that ： "But once I got to campus, it was a completely different ball game that no one really prepared me for."

现在她对大学的理解是：“一旦我进入学校，情况就完全不同了，没人真正为我做好准备。”

But once I make a decision.

但是要由我来做决定。

Okay, but once you get in, bring my key right back.

是的，一旦你进到屋里，就马上将我的钥匙还回来。

Some puzzles look difficult but once the solution is known are actually quite simple

有些谜语看似难解，可一旦知道了谜底其实十分简单。

This book was famous once, but nobody reads it today.

这本书曾名噪一时，但现在却无人问津。

But once these plants use up their stored reserve or tap out the underground supply, they cease growing and start to die.

但是，一旦这些植物耗尽它们储存的水或者用完地下水源，它们就会停止生长并开始死亡。

But once the sea walls almost put the village in great danger.

但有一次，海堤差点给这个村庄带来极大的危险。

He tried to speak, but for once, his voice had left him

他想说话，却一时语塞。

Some puzzles look difficult but once the solution is known are actually quite simple.

有些谜语看似难解，可一旦知道了谜底其实十分简单。

But once outside, he knew he had made a mistake.

一出来，才晓得自己的错误。

But once their use in determining seasons was realized, their importance to agriculture became very great.

但一旦意识到了它们在判断季节中的用处, 它们对农业的意义就变得至关重要.

"An individual's genetics has a big influence on their height, but once you average over whole populations, genetics plays a less key role," he added.

他补充说:“一个人的基因对其身高有很大的影响，但是一旦把他们的身髙平均到整个人群中，基因的作用就不那么重要了。”

I? expect to pass through this world but once;

在这个世界上，我只能一次性走过；

But once the news of your father's illness becomes public.

但你父亲重病的消息一公开。

Now, she attributes much of her understanding of college to that: “ But once I got to campus, it was a completely different ball game that no one really prepared me for. ”

现在，她将她对大学的了解归功于那个项目：“但是，当我进入大学之后才发现，情况全然不同，没有人真的帮我做好了准备。”

The swan is said to sing but once in its life-when it knows that it is about to die.

据说，天鹅一生只唱一次歌，只有在他死期临近时才唱。

But once this opportunity came, the consequences would be far reaching.

但是一旦机遇来临, 后果将影响深远.

But once they do, there's no going back.

但是一旦开始反抗，就义无反顾。

Your brother is happy with his new girlfriend, but once he stops seeing her through rose-tinted spectacles, he'll realise2 that she's not right for him.

这正是一个过于乐观看待问题的例子。你哥哥对他的新女友很满意，但一旦他不再戴着玫瑰色的眼镜看她，他就会意识到这个女生并不适合他。

Opportunity knocks but once.

良机难再.

But once started, it is of course a continuous process.

但是这个一旦开始，它将是持续不断的。

Athens was not in the farthest background of his mind, but once man has a great and good idea, it is never completely lost.

雅典并不位列在他脑中最深邃的背景中，然而一旦人类有了一个伟大而美好的想法，那就永不会消失。

Estela started to say something but a gesture from her husband quieted her at once.

埃丝特拉正要说些什么，但是看到丈夫的一个手势，马上就不说话了。

But once we put him out.

但是一旦我们把他麻醉。

Cannot step on land but once every ten years.

不能上岸，他每十年才能踏上土地一次。