But how and when did it happen?

但这是什么时候怎样发生的呢？

youdao

Iris: Wow! When did it happen?

艾瑞丝：哇！什么时候的事？

youdao

Event: When did it happen?

事件：何时发生？

youdao

But how and when did it happen?

但这是什么时候怎样发生的呢

耶鲁公开课 - 死亡课程节选

I have to believe that whoever came up with that theory for the first time was aided in coming to it by thinking about the end of the Roman Empire, when something precisely like that did happen.

我想任何人第一次接触该理论,都会自动联想到罗马帝国的衰亡,进而支持该理论,因为类似的事情确实曾经发生过

耶鲁公开课 - 古希腊历史简介课程节选

Even though churchgoers were unsurprisingly more likely to oppose divorce, they were both less psychologically affected by marital separation when it did happen, he said.

BBC: NEWS | Health | Religion 'linked to happy life'

When Venus did have a chance to tighten things in the second set, Serena made sure it didn't happen.

NPR: Serena Williams Routs Venus At Family Circle