Do you know if he's married?

你知道他结婚了吗？

《牛津词典》

Excuse me, do you know if there's another train later?

打扰一下，你知道一会儿还有火车吗？

youdao

Jenny, do you know if your mother will come back tomorrow?

珍妮，你知道你妈妈明天会不会回来吗？

youdao

In a poker game you do not want to let your opponents know if your cards are good or bad.

VOA: special.2009.11.22

You know, if I had like shells and peas here I could make some more money. What do I do?

要知道，如果我喜欢贝壳和豌豆的话,那么我可以赚更多的钱？

麻省理工公开课 - 计算机科学及编程导论课程节选

Do I have two yes answers if you wanna check two conditions at once? You know, this might seem to be a bit of a new context for some of you but consider a typical website.

我能不能对两个条件同时判断,来看看它们是不是都为真？,这些概念可能对你们中一些人有点新颖,那么就考虑一个典型网站。

哈佛公开课 - 计算机科学课程节选

So how do you know if your best supplier or customer is about to hit the skids?

FORBES: Small Biz Bum Alert

How do you know if your network is strong enough to support you professionally and personally?

FORBES: Test The Strength Of Your Network

My fellow immigrants, my fellow Americans, how do you know if you are a Republican?

BBC: NEWS | Americas | Full text: Arnold Schwarzenegger's speech