Do you have a minute? I've got something to tell you.

你有空吗？我有一些事要给你说。

另外，助动词Do也可以省略，直接说成You have a minute?

Mr Hughes? You have a minute? I would like to introduce our company structure to you first. 

休斯先生吗？您有时间吗？我想先给您介绍下我们公司的结构。

Are you available?

大家都知道available的意思是“可利用的，可获得的，可找到的”，但它也可以表示“（人）有空，有时间”。

释义: Someone who is available is not busy and is therefore free to talk to you or to do a particular task.  有空的，有时间的

Mr. Leach is on holiday and was not available for comment.

利奇先生在休假，没空作评论。

I'm available next Thursday if you want to meet then. 

如果你想碰头的话，我下星期四有空。

Can you spare some time?

spare time是“业余时间”的意思，其中spare是当作形容词使用。当然，spare作动词来讲有“匀出，抽出”的意思，所以可以使用Can you spare some time？问别人“你有空吗？”

Can you spare some time to go shopping with me?

你有空和我一起去购物吗？

When do you have time off?

have time off是个固定搭配，意思是“休息，有空，放假”，所以When do you have time off？就是问别人“你什么时候有时间？”，是不是很容易记住呢？

When do you have time off? I will give a lecture in your university next week and I hope you can be part of it.

你啥时候有空？我下周在你们学校有个讲座，我希望你能出席。

其他相关表达：

① at liberty  有空，有时间

I will visit you as soon as I'm at liberty.

我一有空就会去看你的。

② have no leisure for...   没有时间...

I'm far too busy right now. That's why I have no leisure for entertainment.

我现在太忙了，所以根本没时间娱乐。

③ occupied   没空，正忙

I'm occupied this week.

我这周没空。