More elements can be added to a realized list when and only when, access is required.

只能在需要访问时在现有列表中添加更多元素。

youdao

Presumably the endpoint would then receive RSS item fragments when and only when that resource updated.

这样推断，端点当且仅当资源更新时才会收到RSS条目片断。

youdao

The abstract data buffer allocates the memory blocks when and only when the actual data becomes available.

抽象数据缓冲区仅在实际数据变得可用时才分配内存。

youdao

This is when a bone is bent and breaks along only one side, like a young stick of wood.

VOA: special.2009.02.04

And only when one has accepted that, is there any possibility of scoring a bull's eye.

只有当一个人意识到这一点，才能够射中靶心。

普林斯顿公开课 - 人性课程节选

So that's the only change we need to make there and watch what happens when we actually run this.

那就是我们需要改变的,并且当我们运行它，会发生什么事情。

哈佛公开课 - 计算机科学课程节选

Sad as it may be the trade is bullish but when and only when the Federal Reserve moves forward with another round of liquidity.

FORBES: How to Trade QE3

They returned fire with 50-caliber machine guns, they also returned fire with their M-16's -- Marines pointing out of the top firing, but not indiscriminantly, that is something the Marines point out -- only when they were fired upon and only when they could see the flashes, did they fire back.

CNN: Martin Savidge: 'Pitched battle that went on and on'

She said there were lots of pieces of evidence that when put together, could look different from when they were considered separately and it was only when the investigation was completed that they could look at all the pieces of evidence together.

BBC: NEWS | UK | UK Politics | Key points: Cash-for-honours hearing