I will tell you the answer for once and for all.

My infant for once lay quiet in his cradle.

我的婴儿这一次总算安静地躺在摇篮里.

For once, he was taken honestly aback.

这一次, 他可是真正地大吃了一惊.

For once, she lost / dropped her customary reserve and became quite lively.

这次, 她一反平素的沉默寡言,表现得很活跃.

Her comfortable voice seemed to soothe James for once.

她安慰的声音好像总算使詹姆士平静下来.

"For once," he said, "the joke's on me. And it's not very funny."

“他说：“这一次玩笑反而开到自己身上来了。这一点儿也不好玩。”

He guested for one or two League sides.

他在一两支联赛队伍中做过外援。

I have had enough obloquy for one lifetime.

我一辈子受够了诽谤.

You're talking over a thousand pounds minimum for one course.

你说的可是一门课程收费至少1,000英镑。

There's room for one more piece of luggage.

还有地方再放一件行李。

I'd like to change this dress for one in a larger size.

我想把这件衣服换成大号的.

I don't believe for one minute she would have been scared.

我压根不认为她会有所畏惧。

He is into me for one hundred yuan.

他欠我100元.

I'm under contract to teach here for one year.

我按照聘约要在这里教一年书.

Stop for one moment and think about it!

稍停片刻，想一想！

Well , for one thing, he's my sister's boyfriend. Ann talks about Jack all the time.

首先, 他是我妹妹的男朋友. 安整天就是杰克长杰克短的.

It means getting some help for your addiction for one thing.

意思是能对你戒掉毒瘾有所帮助.

Don't set him the task. For one thing he's old; for another he's in poor health.

不能让他去干, 一则年纪大, 二则身体弱.

For one thing, they simplify the design of a rocket engine.

首先, 它们可以简化火箭发动机的设计.

You get a low mark, for one thing, because you did not do your homework.

你得到低分, 原因之一是因为你不做作业.

This story is unsuitable. For one thing it's too long, for another it's too dull.

这篇故事不合适, 一则太长, 二则太乏味.